If price is the issue. get a 5150 II, incase you didn't know (which I'm sure you do) they're the exact same amp as the 6505+ but with a different badge.
I wanted a 6505+ but ended up wit a 5150 II because I got it for half of what a 6505+ fetches new.
Tone wise...
Balls - 6505 has more raw, in your face gain, the 6505+ still has an unbelievable amount but slightly more rounded and tamed.
Low end - 6505+ low end is tighter, but the 6505, being looser, is 'bigger'
Flexability - 6505 + has much more
Footswitch - 6505+ is better
Biasing optinos - 6505+ has external bias but it's not really worth using, so they're essentially the same.
Mid focus - 6505 is more low mid focused, 6505+ is more upper mid focussed and a brighter amp.
Boosting - If you're used to using a boost alot, I'd go more towards the 6505, the + doesn't take a boost as well on the lead channel, IMO.
Cleans - Much more usable on the 6505+ I personally like my 5150 II cleans, not amazing but they make do with a CS-3 up front, kinda.. nice.
