I've had one for six months or so and am really pleased. You don't have to worry about light conditions and set up is simple...no wires, no nothin'.
You can select which velocity range you want to use (rifle,handgun, archery) and after a short learning curve the only time that mine has missed shots is when I've been switching between handguns and rifles and forgotten to reset the mode to the correct velocity range.
I've found that if I turn it off while I'm setting up with another rifle, the batteries last longer and I've found the "doppler" trigger feature has worked best. It takes AA's and I've gotten pretty good life out of them but always have some spares in my shooting gear.
IIRC it won't clock above 4000 fps and there has been some concern about 17 caliber bullets but mine has had no problem seeing 22 Ballistic Tips or V-Maxes above 3800 fps.
