I've been living with the Vandies for years now and they definitely play loud enough for me. However, no home audio speaker should be used for "jam" sessions. You tend to over heat the drivers so that when you're done and you turn off the speaker they weld themselves in place. I've seen it happen on non-Vandersteen speakers.
That aside, the Vandersteens come with a comprehensive manual. If you follow the instructions you can easily set them up for your self in an afternoon. I do all of my own calibration nowadays.
I can't compare them to the Verity Audio since I haven't heard them. However, the 5s do Rock! The bass is stellar and the rest of the music is totally seamless.
As for amps, you can definitely go with less power if you don't turn them up too far. However, I'd stick with a 100 plus watts per channel at a minimum for any solid state amp. My favorite is still the BEL 1001, but they're hard to find.
I suggest that you go talk to your Vandersteen dealer and talk it through with him.