Is that you Randall Smith??
I'm joking.
You hit on a lot of good points. I've owned mine for almost 2 months now and continue to discover some great tones, especially in channel 2. Its a challenging amp but I'm glad I stuck with it and it sounds phenomenal on recordings. Like I mentioned in my NAD post when I acquired one, I think the biggest issue with this amp that brought it a lot of attention ever since its release is the expectation of that god damn IIC+ mode. If you take that mode out of the equation, you would only hear about 1/4 of the complaints that this amp brings. In fact, 2 of 3 common complaints are in relation the IIC+ mode. The 3rd being the harsh highs the amp can put out depending on your signal chain.
Lets break it down;
Common complaint#1: Amp has lack of balls/no bass
This comment HAS to be coming from folks who went straight to the IIC+ mode and didn't pay much mind to the rest of the amp. The amp has plenty of power, punch and low end on every other mode, in fact in excess on some of the modes which is the culprit of the flubby lows you also hear about. You rarely read on forums specifically which channel/mode the complaints are coming from which leads to a lot of confusion of the amp.
Common complaint#2 IIC+ mode is nothing like the actual amp
Rather than be a dick and say "well, NO SHIT!", what did people actually expect? Its built with newer and updated components, most notably a completely different PT/OT which is the heart of any guitar amplifier. Not to mention, its integrated into a very complex circuit which will also effect the tone.
@MistaGuitah I have to disagree with you that you can get an authentic IIC+ tone out of the amp. All Mark series amp have their signature "core" tone, but it doesn't even come close to the depth, humongous punch, feel or ratty highs of the actual amp. I even tried Dougs settings in the manual and sorry, still no dice. The MKIV mode however is at least a lot closer to its claims, minus the sub lows the actual amp puts out. But at least the feel is there, the compression and the unique gain texture is present. The MKIV is a special amp. Its the mean bastard child of the Mark family IMO.
In the end, I feel like it depends on how you approach the amp and what the uses for it will be. Guys who need an amp that can cover a lot of ground, especially those in cover bands who gig a lot and need the ultimate in versatility are happier than a pig in shit with the amp. Others who were wanting a versatile hi gain amp with a snappy and tight low end are also generally very happy. I'm finding its mostly the people who were counting on that IIC+ mode to be an exact replica are the ones who are the most disappointed and disgusted with the amp, followed by others who are new to the Mark series and have no clue what they are diving into.