I have not heard the Janszens, though many here rave about them. With respect to the Nolas, I think the Metros may be just a little bit too big for your room. My room is the same size as yours, and Nola had recommended the Micro References, which work perfectly in my room. Soundstage is good-sized and very open, with excellent location of instruments and images in the soundstage, though probably not as big a soundstage as the Maggies--very few smaller speakers can pull off that feat. I know Nolas sound great with tubes (I use a VAC Phi 200), and given the size of your room I think that your amps should work, though you might want to bring them to the seller of the Metros to hook up and make sure. I would also suggest that you not necessarily give up on the Vandys, as remember, they have a separate amplifier built in to handle the bass, and I think 50 WPC should be enough for the mid/tweeter. They may be a bit too large for your room, though.
A couple of other things about the Nolas: if your room is heavily damped, or your listening chair is low (and if these things can't be changed), I would not recommend the Nolas as highly, they do much better with a somewhat lively room (diffusors would be fine) and they can sound a bit polite and dull in the treble if you sit too low listening to them, in my experience.
A couple of other things about the Nolas: if your room is heavily damped, or your listening chair is low (and if these things can't be changed), I would not recommend the Nolas as highly, they do much better with a somewhat lively room (diffusors would be fine) and they can sound a bit polite and dull in the treble if you sit too low listening to them, in my experience.