Lean Xtreme is PCT - I think it has cortisol blocking capabilities. Well I'm pretty sure it does but not exactly sure what ingredient is achieving this. It contains time release sulbutamine, I think, but would be at the lowest strength of the 3 products AX have ... Stim X, SX and Lean X
Slim Xtreme is time release sulbutamine supremo. It combines a heap of stims and lasts all day. Its a hardcore fat burner, which you can also buy a booster to get added kick.
Stim X is more pre-workout type stuff. SX is a unique product and IMO there are no real competitors. I'd use it as a nootropic rather than a fat-burner.
Basically Lean Xtreme is good at its job, PCT fat burning and cortisol blocking. It ain't a generic fat-burner however.
Hope it helps. Perhaps the reps can get onboard on this one to agree, disagree or tweak.