I really like the K-9 products. I've never had a bad one in any of the shops I worked at. Mine is a K9 fluffer. Love it.
I have also used Challengeair and they were good but took a while to warm up.
The metroair ones were the best of the cheap ones IMO.
If you have multiple size dogs I can't recommend variable speed dryers enough. Basically it has a little rheostat on it to control the air being pushed.
I Love, love, LOVE the old k-9 stuff. I HATE the newer lines. They're just not what they used to be. Sometime in the last five years, quality has gone way down. After I came back to grooming from the Army I was really disappointed in the newer k-9 equipment. I bought one that literally was in the shop over and over and over to be fixed and finally dumped it for a b-air (after I had officially spent more money fixing it than I originally paid for it, within the first six months!), which I love. IF you can get your hands on the old K-9 products SNATCH, don't even freaking hesitate, if you're looking at newer models, my advice is to run. Don't look at the model, either, you need to look at when it was actually made. A k-9II that was produced 7 years ago is a way better bet than a k-9II produced in the last few years. IME, anyway.
Small dog in my shop is under 35lbs, Laur.