#1
Both amp seems similar to me. Is there any difference between them or it's just the company tackticks for selling. Which will be good for home practice?
#4
It looks like the only difference is the 15X has OVERDRIVE, DISTORTION, METAL, METAL STACK while the 15XL has OVERDRIVE, DISTORTION, METAL ZONE, EXTREME.

Not sure on the difference between metal/metal stack and metal zone/extreme

Although, if you're looking at purchasing one of these I'd suggest one of the rolands that has modeling of other amps, it's very versatile especially on a budget.
[img]http://cdn.gs.uproxx.com/wp-content/uploads/2012/05/v.gif[/img]