My 2 cents: They're different, one isn't better than the other.
It's more a matter of how you like to mix the ingredients. The V seems to me to lean more into high gain. The VII seems able to do different styles the V doesn't have.
They're each great in their own way; it isn't a matter of one being preferable to the other, they're both terrific. So the choice is more dependent on your style and needs.
The V has cleans based on the Lone Star, and brings the wood on the gainier side with fewer 'crunch' or 'edge of breakup' options. Mine was superb, though I never used Channel 3 because I'm a lower-gain player. That's why I got the Lone Star and sold the V, even though I really dug my V.
It's been quite a while since I had a V, so I don't have as much of a handle on what I loved about that amp - but my overall feeling is it'd be cool to have both!
The VII's Thin mode is a more Black Panel alternative to the standard Mesa clean; the crunch mode is a terrific mid-gain option, and Channel 2 can clone most of Channel 1 so you can set up clean or crunch two different ways. The VII has the added IIB and new Mark VII tones available; I use the IIB mode a lot, and the Mark VII mode can be dialed to be
somewhat reminiscent of a Dual Rec to me, though in a way it's also its own thing.
If I was a 'high gain, most of the time' player I might lean more toward the V. It has fewer Crunch choices and it's a very cool amp in its own right. The clean channel is very close to the Lone Star and it also does the Lone Star's Tweed tone (or at least gets pretty close).
The VII is a great choice if you want the spice of a little more variety; for me especially, the IIB mode that can do a lot of things well is a big deal, and I like the Mark VII mode when I want to get somewhere near my old Tremoverb (not exact, of course, but can do that Recto family-ish thing).
For someone who's more of a generalist that needs to access a lot of gain varieties, or wants variations on the same sounds in CH. 1 & 2, the VII's the ticket. But it can also get
tremendous amounts of gain.
Take my thoughts with a grain of salt, in that I don't do the clank-clank, very tight high gain thing. But that's my instant reaction to the question.
Being a member of this Forum has made me a true Mesa enthusiast again; it's one reason I added the Mark VII to my Fillmore and Lone Star setup, and I looked into the Split Back cab and have one on order to match my VII head as a result of one of the posts here. So now I'm getting greedy and gas-ing to add A '90s Dual Rec and a Cali Tweed, not because I need them, but because I'm simply liking Mesas that much and I worry about Gibson screwing the pooch at some point. So I want all the Randall Smith designs just to be that guy!
I'm also old enough that most folks would think I'm completely nuts to still be so into amplifiers. I'm up to 5 amps, but down to 3 guitars - just the guitars that give me the different tones I really want to have on hand. There are days I think, "You live once, do what you love and don't worry about it," and days I feel, "How long are you even gonna be around to get your money's worth outta this stuff, crazy man?"