This is a subject which I explored and studied for a long long time. I lurked and posted previously but cannot recall my login details. I hope the following is of some use and isn't too long.

Note: I'm only talking about Theravadan monasteries.

Being a monk is like practicing in Hardcore mode.

Yes a lot of lifes problems are gone, you don't worry about money or worldly problems. It is a life where you really can fully apply yourself to practicing from the point you wake up until the point you go to sleep, without having too many situations in which doing so would be dangerous or unpractical. You do not have to think about tomorrow or the past a great deal (although your mind will want to). You have very little worries. Just living in the monastery your mind will automatically quieten. You will (mostly) be surrounded by like-minded dhamma people and forge relationships and help each other practice.
You will have the opportunity to meet and talk with highly attained monks in situations that many lay people would not easily get due to the issue regarding a monk discussing attainments with laity.

Yes, (usually) you have a lot of time to meditate , to study dhamma. Because of living in that system and the Vinaya, your conduct and Sila will be tend toward excellent and provide a foundation from which you practice.You will inspire Sila in others, you will inspire others to practice just by them seeing what you are doing. You can focus your entire life towards the Dhamma.

Sounds good.. from the perspective of Lay life. When you have been there a while, days, weeks, months, years - it is HARD. Your freedom and all the little nice things from lay life are gone. You are on Hardcore mode now. You are not there just to do some good meditation, get some attainments, you are there to develop wholesome qualities and have your unwholesome qualities removed. 

As a lay person you may normally practice when you are feeling good, well refreshed, not hungry, not thirsty, the room temperature just right.. as a monk you will be in a community of people you may not always agree with, You will sometimes be very tired, you will sometimes be very hungry, hot, cold, sick, you will be bossed around and told to do things and it will be unpleasant! You will at times have to do unpleasant physical labour. Your comforts gone. The delusions you have in lay life of how 'I am not that attached to much at all in the world' will be revealed!! You will realise that it was all delusion, and that in reality you only thought that because you still had all the nice little things. The nice cup of coffee when you want. The snack. The entertainment. The pleasant walk outside. Freedom. There isn't the 'in another 30 days the retreat ends and I'll go do X'.. This is it. Forever (or until you quit). Often it may feel like your duties and work get in the way of your own formal practice. You will begin to think that maybe the monks life isn't for you. How being a laymen and practice would be really nice......    you could walk into a shop and buy whatever you liked.. like a nice cold pepsi whenever you felt like it. Instead of waiting until you happen to be given one.

As you follow the monastery rules and the Vinaya , you will see your flaws. You will see the Kilesa. You will ooze desire and aversion.

"I" don't want to do this. "I" am too tired. "I" shouldn't be spoken to like that. "I" think my way is better, "I" don't think he is practicing the way he should.

You have to let go of your likes and dislikes.

You can either go with these thoughts and suffer endlessly as some do, or you can observe them.

Your task is to ride it just as you would normally, observe the mind, observe the body, see the characteristics. Follow the 8 fold path.

To be clear, as others have said most Theravadan monasteries do very little towards actually practicing or meditating.
This is because in Buddhist countries they serve more a community purpose, ceremonies, marriages, deaths, blessings. The 'religious stuff'. Buddhism is part of the culture. Some people become monks just because its a better life than starving and being poor, some even do it because they become rich, some do it to get an education. The Vinaya is often not strictly followed. Being there you can easily begin breaking the rules.. and before long disrobe.

Then there are the other type, the small minority, the forest monasteries or monasteries where there are those that actually do practice. The names of many are well known around the world. In these places most people practice, they are strict, they are hard.

As a trend in buddhist countries, the number of places that tend towards being the 1st type is increasing as the modern world creeps in, and the 2nd types are gradually becoming more like the 1st types. But there are still many places left that have a solid training.

There is however no perfect place. You may find somewhere that is a great location but has too many non-serious monks, or a very serious training place that is in a terrible environment. Within the monks there may be a lot of hierarchy issues, bossing around, people letting power go to their heads, jealously. Mean monks. Difficult lay people. You just have to ask yourself 'Is this good enough, is it okay?' Everywhere will have its problems.
You will have to deal with the religious stuff, the chanting, things you will not agree with - but remember, this is their religion.. if it wasn't for doing such things (from which the lay people gain faith and at the least train their sila) - you get your requisites, you are fed and the monastery has buildings.
It isn't just about the monks. The monks and the lay people must work together.

In the DHO community I have seen comments about Theravadan monasticism which I often think is quite ill informed. The biggest thing I often read is about attainments. Many people perpetuate a myth that in the modern world nobody believes being an Arahant is possible, or that attainments are not possible. This is not true. From what I have seen, the only place where this view is predominant is within Theravadan buddhist in the West. In buddhist countries it is not uncommon for people to chat about a 3rd parties attainments. People will talk about which monks are arahants. Monks will talk about lay people who reached particular attainments. Monks will discuss with each other these matters. One thing that monks will not is talk about their own attainments with lay people, as this is against the Vinaya. Some people will claim that some well known monks have done this.. in reality they did not. Usually in these circumstances they were discussing the matter with monks.. but were either overheard by lay people, or the discussion was recorded and a lay person later heard the recording. Other times they just describe what actually happened (the sensory experience) as they reached that attainment and it is up to the reader to assume what it means. It is not uncommon to find books or CD's in bookshops whose title translates as 'A Manual to become a Sotapanna', or to meet someone who says that 1st path is what they hope to attain in this life. Unfortunately, outside of Sri Lanka, English is not well spoken in Theravadan countries - so often unless a person understands the local language - it appears that none of the above is happening, and instead there is just the usual western style books in English. That said the standards for attainments are usually set very high.

One thing that must be understood. Being a monk is not just about attaining 1st/2nd/3rd/4th path. It is lifestlyle/system in which you live as part of a community/sangha - monk and laity, developing your sila, developing wholesome qualities, uprooting unwholesome qualities, assisting others in developing those things, assisting the sangha, teaching the dhamma, being a symbol of the dhamma.. WHILST working towards those attainments... and supporting others so that they may reach those attainments.  

As for whether you should you become a monk.. It depends on the circumstance.  If you are married with children then obviously lay life is probably better suited. It also depends on your motivation. If you want to become a monk to escape from the world.. then you will find the monastery has even more suffering. Start by trying to keep a daily sitting practice in the morning and evening - whilst maintaining 7/8 precepts. Do that for a few months. Then go to a monastery and stay for month. The only will you will know if it is for you is by staying in a monastery and seeing it for yourself what it is like.

If you have the strength to do it, are able to do it AND practice (rather than just surviving) - then there is no more direct a way of practicing the Buddha's teaching. It is total immersion. Ajahn Chah was once asked how he was able to get to where he did - he replied 'I dared'