I've owned a Mark IV and had to sell it after having it for 5 years. I later bought (and still own) the Mark V back when they came out. As a lot of people said, the V gets a lot of shit, because they made the mistake of putting specifically named modes "Mark IV" and "Mark IIC+" on the Mark V. Yes, neither mode is actually a match for the tones that the modes are named for...although, the "Mark IV mode" is actually a bit closer than the "Mark IIC+ mode". Despite this, anyone who says the MV isn't a good amp, simply don't know what the fuck they are talking about. Most of the stooges that say this, "verified" this by demo'ing the amp for less than an hour and never took any time to dial in settings...and of course the other reason falls back on the mode naming. The MV is actually capable of a whole lot more than the MKIV. And, many believe (including me) that the MV has a better clean channel than the MKIV. Now, the MKIV has an amazing lead channel that can not be truely duplicated by the MV, although it's not way off. There are times, when I do miss the MKIV, because of this. Although, I am satisfied with the MV more overall. I the both amps are very good in their own right. Like most, I never really got into the MKIV's crunch channel. Where as, just about every channel, mode, etc is usable to me, on the MV. Honestly, I still wouldn't mind picking up a MKIV again down the road for the right price. The MV is here to stay though.