Hi there,
I have used SizeOn and Green Mag and I have to say that I like Green Mag better for building muscle on MY body, but SizeOn is a damn close second. SuperPump is, from what I hear terrific, but no experience personally. Also, don't forget your BCAAs- Xtend is awesome for during workouts and tastes good, too.
As far as ON bloating you- I personally have never experienced that but that doesn't mean it won't happen. You might have to go off of it and see what your body does.
Lastly, if you want to gain muscle, I would cut back the cardio a little. That can impeed muscle gain. Then you can kick in the cardio more when you want to cut.
Good luck!