omrons are higher quality switches.

yes, it is infrared. both are invisible.

i have both razer DA 3.5g and imperator.
i personally prefer DA's sensor, but the shape of imperator.
due to my smaller sized hands, i prefer the ergonomics of imperator > DA.
thus, i am using imperator instead eventho its sensor suffer from z-axis error, which i'd rather face than an uncomfortable mice.
my opinion, try both out, your opinions may vary from other forummers as it is very subjective from one person to another.

for me, i have 3 razer mouse, all of them, well over a year, and still working without a problem.
on a sidenote, imperator's scroll wheel feels much better than DA's, at least for me.

damnn, some hardcore razer fan~ how much for those? RM700?

the stealth version is.... mainly due to the matte finish and not the usual razer glossy....

no clicky sound anymore