Out of those 2 on eBay. The Infocus 4800 would be the better deal by far. Better contrast, double the bulb life, was manufactured in 2003 and stop shipping March of 2005(compared to 2001 for the NEC) The Infocus is surely quieter. The only plus for the NEC is that it has DVI over the Infocus RGB Component. They both have about the same focal lenght to produce a 60" image.
NEC to get 60" is min.8'1" max is 9'8" sweet spot would be for around a 96" image at 15'8" away.
Infocus to get 60" is 7'4" max is 8'9" sweet/good spot for around a 96" image at 14'5" away.
OOPS have a friend who has a Backup InFocus 4800, By chance it happens to be one of the only (I'm sure there are tons more) that can not be ceiling mounted upside down. Not sure on the NEC.
I see that the eBay seller says its an open box for the InFocus. But does say 7 day DOA. So if by chance you get it, take a look at the bulb. Any carbon build up and it is quite used. And then BMXTrix would by all means be right, because after 500.00 on projector and you have to buy a 300.00 bulb right away, then you could have gotten one of the choices he has listed....