I was on the 3x5 but I wasn't very consistant and missed 2 months of workouts, so that knocked my progress up a lot.
Now I'm on the 5x5 and I don't have a real set diet, but I'm eating lots of whole grains, chicken, milk and generally just a ton of food in general. I usually eat around 6,000-7,000 calories a day so I'm definitely eating enough, I'm just pretty tall as I'm 6' 5" so any muscle gains won't show up very well on me at least not until I put on a TON of mass.
Edit: My stats
6' 5"
225lbs
17inc Arms
34inc Waist
25inc Quads
Max 5 rep lifts
Bench: 150lbs
Squat: 200lbs
Deadlift: 245lbs
Military Press: 95lbs
Barbell Row: 185lbs
I currently just started Bill Star's 5x5 weight training program, I think it will be good for me.