I have three optical mice: Intellimouse optical, Logitech Optical Mouseman Wheel, and a Micrsoft Intellimouse with Intellieye.
My observations:
Logitech - smoother, but smaller then the other two. However, it feels much sturdier and longer-lasting. Please say you can do weird stuff like "overclock" it with the logitech software that comes with it but I just use it normally
Intellimouse optical - much bigger than the Logitech one. It's made so both left and right hand people can use it. It's, in general a good mouse. Because it's sides are always sloping outward, it feels lest comfortable because you don't feel like you have complete control of it (the logitech, by comparison, drops off on the side so that you can grab it completely)
Intellimouse with Intellieye - the basic mouse with optical technology, even though it looks like the prehistoric mice is my favorite because of the ergonomics (fits only right handed people). Total control over the mouse. This thing is solidly constructed. The sensor peeps through a tiny hole and general housing is fantastic.
Button-wise, the intellimouse optical wins hands down because it has an extra button on each side (shortcuts to move back and forward in IE by default). But if you're cool with going up to the toolbar and clicking "back" manual, I'd say go for the simple Intellimouse with Intellieye.
Just my .02!
-S