I really appreciate all these posts, I actually do NOT own a Rectifier, but have heard a bunch of them. I own a MkIV and a Stiletto I Trident head. I am a pretty big MKIV fan, and frankly, though I am considering a MK 5 Head, I played one of the new Multi Watt recto's recently in the store and I was very impressed. yeah the Mark and Recto are very different indeed, but both have amazing, yet different tones. I would not feel deprived owning either of them, yet I am not as intimately familiar with the Recto's.
I remember playing a few of the older Recto 2 channel versions in the stores new, back around '98 and really liked them, though I don't know what "version" they would have been that year, but I do think they sounded better as far as I can recall than the more recent 3 Channels of the last couple years.
To my ears, something DID seem different about the brand new Mesa Dual Rec Multi Watter. I believe the only way I can describe it is a better (warmer) sounding "pushed" channel 1, and a pretty bitchin' channel 2 all around, and a less "fizzy" channel 3. Neverthess, I admit pllaying a Mark IV the last 5+ years, in addition the Stiletto the last year or so, I am but a novice when it comes to the Recto's and plan to evaluate a little more, though like many players here I also have heard the Recto's recorded by countless bands that I listen to on a farily regular basis though that is not quite the same as playing one yourself.