I would not get a round or octagon kiln — they are not as effcient in usable space as a square kiln is.
I have purchased all my kilns on line — two from Clay King and one from D&L Art Glass (you need a wholesale account to buy at D&L). I have two Paragons and a Skutt — both manufacturers provide excellent products. So far, knock on wood, I’ve needed very little support. What I have needed was easily accessible on-line or by phone/email.
I love the viewing window. I do not notice significant cold spots in any of my kilns, and really, if you’re worried about efficiency, that goes out the door (literally) the first time you raise the lid to see what is going on inside the kiln. I’d rather peek through the view window than open the lid. In some instances, I still open the lid but most often I can check the progress of things through the window. I would not buy a kiln without one.
I have the Fusion 14, which is shown here at Clay King: http://www.clay-king.com/glasskilns.htm
My only complaint with the F14 is that when I do high temp firings (1650 degrees) (combing, raking, pot melts…), it takes it longer to get to temp — it’s a fairly large kiln for 120V. However, with almost everything I do, it has served me well. The F14 is $800, delivered, from Clay King, or add another $100 for shelf kit and view window. Make sure to factor in shelf and kiln posts — they may not be included in what your local guy is quoting.
They also sell the Fusion 16 — I don’t know much about it but I assume it is similar in performance.
Jester’s Baubles Fused Glass Designs