#1
Differences in sound? I've only personally played the XXX.
To me:
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One of the best replies ever.

In the same thread

Do you love Arsis?
#3
The 6505/5150 has darker, fizzier, and more polished gain tones.
The XXX has better cleans, brighter, more in your face and crunchy gain tones.
#4
^Yeah, that's pretty much it. From what I've heard from the XXX, 5150's have a lot more low mids.