To give some insight on maintenance- I've used my V4B for 20+ gigs and have only had to service it once. I was a little careless one night and slammed it into a door which caused a soldering joint to break. It was a super simple fix and it only cost me about $40. Like others have said... The V4B is an incredible amp. I also have an SVT-CL, but it's more or less a backup for the V4B at this point.
I did a cab shootout between the 212AV and the 410HLF earlier this year. Personally, I love the V4B paired with the 410HLF. I tend to favor low-end more than mids (I absolutely love the ultra-low switch on the head), but both cabs sounded great in their own way. That being said... In your case, I would highly recommend the 212AV for going up 3 flights of stairs. The difference in tone isn't worth the hassle in my opinion.
Hope that helps!
I went the opposite route--SVT on a 212AV. I used to use a 410 HLF but the 212 is much easier to haul around and has the mids and similar in sound to an 810 which I prefer. But the HLF is a great cab for lows.
) V4-B's sound good but there are certain situations they just don't have the head room you need.
.and I've had most others.
) so the V4B ain't getting run hard often. .. andthe Super Bassman ain't getting run HARD virtually ever. But. ..unless I'm gigging HARD every weekend AND running the tubes HARD