Excellent controller, the best wireless controller I've ever owned (including the Wavebird) and the best wireless controller on the PS2 period.
Few minor nitpicks:
-The D-Pad seems a bit weak IMO, function is fine but the pad itself seems flimsy
-Pressure sensitive buttons are not as good as the DS2 (see above post), makes Metal Gear Solid 3 CQC frustrating when you keep slitting people's throats instead of grabbing them (LOL)
-Analog calibration is sometimes required, after months of play in SOCOM II and SOCOM 3, I booted up to find my left stick (while in place), moving my characters while I wasn't even holding the controller (I even tested to see if the stick was loose), THANKFULLY you can find a way to "recallibrate" the analog sticks (reset the controller to defaults) on the Logitech website (excellent support)
-When rebooting a PS2, sometimes the controller will fail to communicate with the receiver (worst offender of the bunch), so a complete shutdown is often required to get the controller to sync with the PS2
HOWEVER...(end of criticism!):
-Excellent analog sensitivity, makes it great for shooters (see: DIEHARD SOCOM fan)
-Battery life is excellent, I use 2 NiMH AA's (2500mAH) and it lasts forever (I've had it last a solid 4 days of straight SOCOM 2, prob. 6-7 hrs daily)
-Great form factor, very comfortable, I don't find it that heavy at all
I use this controller more often than a DS2 (unless it comes to D-Pad or needing Pressure Sensitive face buttons). In GT4, I actually prefer the DS2 just because there isn't enough friction in the sticks to keep my thumbs on them, however, for acceleration and deceleration the Logitech is superior all the way.
Great controller, easily worth the money and superior to the DS2 (in many factors).