1. What makes owners of Mesa gear like it so much. (general question about Mesa gear ie build quality, support and availability) - for me it is extremely well designed and built. I have called upon customer service twice (not related to problems) and they have been very good.
2. What is it that made you pick that particular amp over others. (in respect to other Mesa amps or cabs and maybe in respect to other manufacturers gear) - my first amp (Bass 400 in 1988) was bought solely on a review that called it the Rolls Royce of bass amplification. I have used Mesa stuff entirely since then (save for a short period with an Ampeg PF500 and 1x15 cab). I have had a 400+ and also have a Walkabout and an M-Pulse 600. In side by side comparisons with other Mesa amps I have noticed some commonality in eq and sound.
3. Is there a favoured set up that majority of owners prefer or would prefer. - I'm a 15's kind of guy and started off with a pair of Diesel 2x15' but now use two Subway 1x15s.
4. Can you describe briefly your preferred tone (ie, warm, mellow, mid-punch, heavy bottom end, high top end are just some things i can think off) - think Bohemian Rhapsody.
5. what bass do you generally use with it. (just to give me an idea of whether your bass is passive, active or has a deciding influence on how your tone might sound) - Precision with flats although I started with rounds.
6. Finally what Mesa gear would you recommend for a Mesa Virgin like myself playing mostly classic rock with a Jazz bass but occassionally depping for other music genres doing pup / club material. Depends on what you want but I would be looking at a D-800 and the Subway cabs (whichever suits you best).
The thing to remember with Mesa stuff is the eq is not straightforward. It took me 6 months to figure out how it all worked together (on the Bass 400 when I first got it). The eq is very sensitive and little tweaks can make a big difference.
I have not had a single problem in the 30 years I have been using their gear and still have my original Bass 400. Wonderful kit and worth every penny. Toured with me all over.