hey Tom
I only got it yesterday evening and it is a STEEP learning curve.
I believe it is as good as they get in multi/processor type things unless you wanna pay 1,000's.
It has so many settings it's unreal.
A cool thing (big sell for Boss) is you can set channel changing or effect changing by guitar volume or more over "pick attack".
You can set any head to any cab then set a mic in different places on the cab and at different distances (told you it is complex).
Bear in mind my trials and tribulations before (with moving home to UK) so only have a Microcube lol.
However, first thing you do when setting this thing up for first time is input the device (amp,cab,mixing desk,etc.) you are going into so it can assign the correct output.
I cannot comment really but thus far I do believe it's the "dog's dangly bits" LOL
Remember, it is CMOS so is digital, not a valve pedal. That being said it should not influence tone/sound anymore than a non-valve pedal and I would hazard a guess alot less. I am impressed with the build and array of this thing.
I have been scoping GTCentral (GT6/8) user group and they post patches. Also a free patch editor. It has a midi out you see so can be connected to a pc (amongst other things) to record etc.
Sorry could'nt help more.
Nick