Last weekend I picked one up at the local used shop.  Sounded sweet.  Did a bit of research and was surprised to see such mixed reviews.  A lot of banter regarding it as a Marshall wannabe that can't hit the high gain tones.  "Perfect for typical 80's rock and that's about it" I read.  I'll tell ya, it only took about 10 minutes playing around to find some sweet spots.  It reminded me of my Fender era Sunn, less a bit of gain.  It also reminded me a bit of a Mark IV, again not dimed.  That said, rolling up the bass this think ripped better than "typical 80's rock".

I'm new to the forum, so cheers.  Any comments, suggestions, or overall observations/experiences with this amp much appreciated.
"I definitely don’t write all my music in a blackout, like I used to, although I did come up with some good stuff in a blackout."
-Matt Fucking Pike
Typical forum stuff. The people who actually have one know better. This has been one of the most popular Carvin amps (and re-issued several years ago). 
It was never designed to be a Marshall wannabe, but if you'll set it up next to an early Mesa, you may detect some DNA. That maybe why it reminded you a bit of a Mark IV. When I bought mine, we set it up next to an '89 Mesa at the Mesa factory store in Hollywood and just compared for nearly an hour. In the end, through I could have afforded either, the boys at the store and I decided there was no reason not to get the XV112B (B = "British voiced speaker). 

Mine has EL-34s and came that way. Does yours have 6L6's? Some came that way. It's a very balanced amp, with really good Fenderish cleans. It's not an amp designed for huge gain, but I've never had an issue getting it there. The controls are active, which means that they extend a lot farther up AND down than most amps. Mine is a 1x12 combo, but I've unplugged the internal speaker and run a couple of 4x12s from it, and the silly thing will put a Marshall back on the trailer. The older ones, like yours and mine, have *serious* transformers, and those are part of the difference you're seeing on the bass end. I replaced the Brit speaker in mine with an EV-L for a while, and that thing seriously punched.  And they have a good spring reverb system. The reissues are a bit different, with smaller transformers, less volume, and a digital reverb (which may actually be better, in my estimation, than the spring tank). 
I really want to hear one in person. I love the Mark amps, and I have seen the comparison often, naturally I am intrigued.

Any chance either of you guys could record a clip of yours demonstrating some higher gain sounds? I don't think I've ever heard a clip that does it justice.
I'm just a kickin' and a gougin' in the mud and the blood and the beer.
Nice amp , they respond to tube changes too , Carvin sometimes gets a bad rap because they take some time to dial in , I have 3 different Carvin but not the X100B or the Leagcy , the V3 gets a bad rap for fizzy sound but once you learn the amp it's so easy to dial out it's not funny

My amps top 4 in order are
1.... Mesa Dual Recto with Strymon Blue Sky

2.... Carvin V3 head

3..... Carvin V3m head

4.... Mesa Mk V head
I don't pay much attention to reviews, as most are written by noob's or shills,  Nice score BTY,   I love the old obscure stuff, 

Amps I have at the moment..

Kustom Doublecross with Kustom DC Coupe 412 V30
Kustom 72 Coupe 2x12 combo
Kustom Quad100 DFX 2x12 combo
Bugera TriRec Infinium
Peavey TNT 130 1x15 combo