RE: Cutting while on gear
Like whiffin said, except when I cut I don't mind keeping it going as my strength falls off. So you might find that due to the calorie restriction that you are getting weaker and feeling a bit deflated. If so, you can cut out sets or reps but try to keep the intensity high. ie. heavy weights for 5 or so reps. Your muscles are depleted of glycogen so you probably can't as easily sustain 10+ reps nor do you need to. However, if you don't need to, then there's no real reason to change the way you lift....When I'm on gear and dieting I find I can handle at least the same intensity as when I'm not dieting and not on gear.
The difference between cutting on and off is just like whiffin said, you can cut harder without losing muscle. I typically diet at a 100 calorie deficit without gear, but with gear I'll go for 1000 calories down each day. I can drop enough fat in 1 or 2 weeks to get me where I want (I'm already lean). And during this time I typically won't lose strength or muscle because of the gear.
Another thing, the gear itself makes it easier to lose fat because there are androgen receptors in fat cells that trigger them to 'downsize'. This is the mechanism that explains why men typically have less BF than women.