Honestly it all depends on your mentality. Where as I found bootcamp to be a breeze, some of my other sailors found it to be the most difficult thing they have ever done.
And I disagree with X X, I definately found my AIT much more difficult. (Nuclear power field).
Physically I found the standards hard for me. Considering I was out of shape, but your recruiter will help you with this as you have to do physical training while in the DEP program.
Honestly the number one piece of advice I can give you is. Its a Job.
No matter what your told to do, you must do it. And you get paid pretty well for it, I found it amusing that my fellow shipmates balk at orders. When they yell at you, its not to make you quit its to help you. Its their job to do so. and do NOT take it personally. What they say may hurt you, but it is said and meant to make you stronger, to make sure you are prepared for service.
Also, memorize whatever your recruiter tells you to and gives you in your DEP handbook. you must be able to recite the information off the top of your head, anytime, anyplace, to anybody.
