I have a 1999 Chrysler 300M with about 50K miles (bought it in 2002 with only 27K)
I have had no problems with it that were the car's fault.
(Only problem thus far has been fist sized hail damaging the heck out of the body, costed $7000+ to fix, insurance covered most of the costs)
I average about 19 MPG (heavy traffic, stop and go driving, about 1/2 highway, 1/2 local roads)
When they highway is open, and if I cruise at like 70, milage is around 25mpg.
When dealing with just city traffic, and no highway, all stop & go, then closer to 17mpg for my driving style.
it's not a "fast" car by any stretch of the imagination, however, it's not terribly slow either. (according to chrysler, 6.8 sec, 0 to 60, according to reality 7.5 sec is more realistic)
If you can find one with the "performance" handling package, it makes a pretty big difference with cornering, etc, so I would recommend that.
Otherwise, best of luck to you.
Also, the 300m Is much more roomy then a Maxima, it's also got better handling and acceleration. Though the Maxima will probably last longer/require less maintenance in the long haul.
EDIT:
Here is a pic of my 99 Black 300M
Here is another picture.