The schooling is the most academically difficult thing you will likely ever do. Expect eight hour school days and two to four hours of studying every night. Which two to four hours you spend studying is up to you. Studying is done at the school - you can't take your homework home or back to your barracks room. You MUST be disciplined to make it through. Everyone who gets into nuke school is SMART enough to pass it - not everyone is mature enough. Many times, this means studying when you don't think you need to. Nuclear power school is there to help you pass. Nobody there wants to see you fail. There are instructors available after hours to help you with homework/studying questions. They closely monitor your progress. If you're doing poorly, one of the most common remedies is to require you to study more hours - so, stay ahead of the system by logging in more study hours yourself before you're forced to.
You will be working in a propulsion plant. Think heavy industrial: lots of big, noisy, powerful, machines. (Pumps larger than anything you've ever seen, steam turbines, air compressors, etc) If you are an MM (like I was) a significant portion of your job at sea will be carrying a clipboard with a set of temperature/pressure/etc readings where you keep track of the pressures/temperatures you see in your area. It will be hot and noisy. You will wear ear plugs, or ear muffs. You may be allowed to take off your shirt and work in your T-shirt. As an ET or EM, your working environment will be different in that it likely won't be as noisy or as hot.
Nukes, especially junior nukes, have a reputation for being real book smart, but also for having little common sense. This is the core of nukes catching good natured flak. But, they also know you have what it takes to complete what is universally understood as some of the Navy's most difficult training. So, some of the flak you'll get stems from jealousy. Wear the teasing as a badge of honor.
*If* the Navy says you have what it takes, and *if* you don't know what you want to do, and *if* you don't have a pretty good job (pays good and is unlikely to go away because the economy takes a nose dive) lined up, and ESPECIALLY IF you live in a little podunk town in the middle of nowhere, then Yes, I would recommend it.
But, you have to understand, there will be times that you HATE it!! After one too many 12 - 16 hour days, you will wonder why you don't just walk off the ship (or boat if you become a "sewer pipe" sailor) and not come back. Long hours and hot, noisy working conditions pretty much sum up the down side. However, you will be working with the best of the best. It has been said that someone who isn't even able to lead starving men to chow could lead nukes. Also, you advance very fast as a nuke. I made E-5 before I had two years in the Navy. It it possible to make E-6 with fewer than four years in, but you have to really be on top of your advancement schedule to do that. Plus, the bonuses are the biggest in the Navy.
I was on a carrier, and the nukes were in four section duty in port. This means that every fourth night in port, you have to stay on the ship 24 hours. That may not sound too bad until you sit down with that fact and a calendar. Getting a full weekend (Friday afternoon until Monday morning) is rare. It only happens every fourth weekend in port when you have Thursday duty. If you have Friday duty, you get off from Saturday morning until Monday morning. You get the picture. Because you'll be at sea for at least six of those weekends per year, you'll only get six full weekends per year off. Of course, this doesn't include your 30 days of annual leave, which you could use one day at a time to make some of those partial weekends full ones.
As a nuke, you will have to get to the ship early to start up the reactors and steam plant when the ship is going out to sea. This may put you aboard a day before the ship pulls out. In my case, aboard the USS Enterprise, we set steaming watches (think at sea schedule, instead of in port schedule) a day and a half before the ship was scheduled to pull out. Enterprise has eight reactors, so getting everything up and going takes longer than any other carrier (all the rest have only two larger reactors) and longer than submarines that have only one.
Also, just like every other Navy ship that has existed since they were powered by coal, it may be several hours after the ship pulls back into port that you can get off. The propulsion plants take a while to shut down, just like they take a while to start up.
If you're on a carrier that pulls into a liberty port, you'll still have to stand at sea watches because, even though the main engines are shut down, the ship still needs electrical power and very few places overseas can provide electrical power for a carrier. Six hours of watch followed by 12 hours off watch is not uncommon in this situation.