When i was researching which printers to get for our office of 25 people i was looking at several things and this is what i found:

On comparable priced models:
The cost per page was lower for the Xerox. Xerox was ~3.1 and HP was ~5.5 cents.
Xerox page per minute rate was almost twice as much.
Xerox had more RAM, which makes a difference with large document sizes.
Consumables are cleaner and easier to use.
Xerox tends to jam less and jams are easier to fix.
Xerox tended to be upfront about the cost of consumables while HP you have to hunt this down.
Xerox drivers have fewer issues than HP, in my experience.
Xerox tends to be quieter.
Faster first page print, usally in less than 10 seconds.

I have a 3 year old 6250 with over 300,000 prints on it and it is still going strong. The last thing i had to call a repair person out for was a paper jam, and that was because the sales person tore a sheet of paper to shreds trying to get it out instead of calling me to do it. The only real issue i have had with them is when the office orders really cheap paper that has alot of dust on it, the dust coats the rollers and causes printer jams, but this is fixed by cleaning the rollers, which is not that hard.

Here is the comparison (Xerox 8550 vs HP 3000 - almost the same price): http://www.office.xerox.com/latest/855CC-11.PDF
IMHO, XEROX is the clear winner.

I can also vouch for the Xerox. Nice, fast prints and reasonably priced. I have 6 of them on my network at work.