I've never seen any Kyo's in the field, however I've seen a shedload of 2550's. In most ways they are good machines, reliable and not prone to silly faults. However, you have to be extremely careful how you treat them, sensors can be knocked out of place, parts broken really easily. I tell customers to treat them kindly!
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Up to my nuts in toner and loving it!
I have worked on both and still do. I really like the Kyocera Model's better. The Ricoh are service heavy with the Kyocera the service is pre made for you. Like the drums and developer units come in a box you remove the old ones and you put the new ones in. The Richo's on the other hand you have to rebuild everything peice by peice. For me as a Tech the Kyocera is cleaner and less service is need. Also the parts last longer.