Really digging the 6505 module, honestly.
They def got close to the real deal with it, although I think the Green channel differs from the real thing a little more than the red.
One thing I've noticed with all the Synergy modules, at least through my Syn30 power platofrm, is they all have a little more upper mid presence and a tighter low end across the board. It's the most noticeable on the Slo module, but is also noticeable on the 6505 module.
I personally dig it, as both of those attributes favor my tone preferences, but I can see how others wouldn't like it.
Overall, I really dig the Synergy stuff for what it is - a super close approximation of a lot of amps most people can't afford with good features and ease of use in mind. Could it be better or more accurate? Possibly, I don't know about the circuit stuff but it seems a couple people in this thread think it could be better. Even so, I'm happy with it for what it is.
Also, I absolutely LOVE the IICP module. Like, fuck. I think it's a lot of fun