Sumo 9 and B&K EX442

Any Info and or experience on these amplifiers would be appreciated.
Sumo is Class A rated. Very warm and tube like. Definitely in the class of Threshold or Pass.
Is 500 too much to pay for one, and what about the fan noise.
I used to biamp with two Sumo 9's and have nothing but good to say about them. They were reliable, sounded good and and I did not find the fan noise objectionable.
I have an EX-442, which I use with a BAT VK-31 preamp and inefficient, 9-driver speakers from Fulton. The combination is warm and comes close to what I heard using the same equipment with a pair of Aleph 2s. I paid $450 for the EX-442 on Audiogon, and I consider the amp to be an excellent one at that price.

I also found that B&K's repair facility has fair prices. They repaired the amp for a nominal charge and shipped it back to me in a new box and with new packing materials.
Mark do you know what the difference is between the EX442 and the EX4420 other than looks.

Sorry, but I don't know the difference between the two models. Someone recently posted a link under this Amps & Preamps forum to a .pdf file on the B&K amps. If you can find the post, you'll be able to see all the older models. The B&K website may have some information too.

The post under Amps & Preamps which has the link to the chart listing the specs for all the older models is titled "B&K St-202 vs St0202+ plus". If you scroll back 2-3 pages you'll see it.
I used to have a B+K EX442, it was a low hrs factory rebuilt when I got it. It was a very good amp indeed.
But when I later got a Threshold S/150 and a Forte Model6 along the way. I sold the EX442. It was a good amp but not in the same class as the others. Not sure how it would compare to the Smuo 9.
From my experience, the Sumo is more like the older Thresholds, 400A, 800A and so on.
The B&K is probably a little "lighter" and "faster" but not as warm.
From what I know, I'd rather have to repair a B&K than a Sumo. When class A amps blow, they really BLOW. Also, B&K is still in existence.