Hmmm. Oki would be an interesting brand name in our office!
I would go with the Oki. I think it said 12ppm color. Like I said, they USED to make really good stuff.
The next choice for me, but probably a better choice for you, is one of the Konicas. 11*17 paper handling and 17 ppm looks good. Consumables can be pretty expensive!
I have found that most Staples stores have one guy that is good, knows the stuff and will steer you towards what you need. They aren't on commission, so the pressure isn't there to sell you something, and you will generally get a good, honest answer to your question.
If you want, we have a really good guy in Mass. I can ask him (I usually go on Sat. mornings) what he would do in your shoes. I was going to buy an expensive LCD 19" monitor, and he talked me into a LOWER priced unit!!!