I previously owned two razer boomslangs 2000. It was great about 3 years ago, now it cannot be called a gaming mouse, cuz its not optical. I've used them a lot and the dpi is great, super smooth, up untill the point when your inner rollers start getting stuck while moving the mouse , and it sucks. Only way to go now is optical and the best wireless mouse is Logitech MX700/MX900. I own MX900 which comes with bluetooth hub. I also have Microsoft wireless mouse at work. Compared the two here is the conclusion:
Never get a wireless mouse w/o rechargable hub
Microsoft mouse feels cheap and has weird shape where as Logitech Mx900 has superb quality build. With metallic finish and awesome grip, its best for gaming.
MX900 has no delay and battery never runs out, My microsoft mouse at work has been running on same batteries for about a month now but i notice lag on it, thats why i stoped using it and hooked it up to my testing MAC box.