I was in the Sumarine Service for 6 years, and although i'm proud of my time in the service and have plenty of stories to tell, I wouldn't recommend it to anyone unless they go in at officer level.
I found in general the ratings/nco's are looked down upon by the officers, and by the end of my time, I can truly say I felt demoralised and that I was a lower class of person than an officer. They talk to you very condescendingly.
It probably doesnt help many of the ratings are complete idiots, especially in the sonar branch but I realy felt that by joining at this level, the hierarchy surpressed peoples ambitions at almost every level and although there is a career path to follow, its very much the path they want you to lead, and not so much about reaching your full potential.
I left the service in 2004, at a time when many of my shipmates were leaving with the same gripe. During the last year in the service we were all constantly told there was nothing out there for us, that we were making a terrible mistake leaving the navy etc. Some succumbed and withdrew their notice, but the ones who went through with it and left the service have never looked back. We are all now professionals and enjoying very exciting careers. Teachers, company directors, engineers etc.
To sum it up, join as an officer yes, as a rating, only if you want to feel like your a 2nd class citizen!