I've had this "argument" before with technoob tamere. First of all, these "pro's" who advocate using low DPI's are probably rambo medics with lots of scripts to change sensitivities, turn around when needed, etc., or they said that when most everyone was using screen resolutions of 800x600 AND lower.
The reasoning is simple: at 400 dpi, you'll have to move the mouse MUCH more to cover a given area. You have two options then: a) increase mouse sensitivity (by LOWERING the sensitivity Cvar value), but then unless you're running at a very low resolution, your precision will go out of the window, because each little movement of the mouse will make your aim jump lots of pixels. b) decrease mouse sensitivity (by INCREASING the sensitivity Cvar value), and then you'll have a great precision but a very narrow angle of movement (this is a favorite setting for rambo medics). Don't even think of playing with RG's or panzers with these kind of settings unless you do not intend to move your aim around a lot (ex., when camping with a panzer pointed at a spot enemies will pass through).
About acceleration, that's a given, you want that turned off. You can't be precise if your mouse is accelerating while you're moving your aim.
Now there's this fucking MYTH, unfortunately widely spread, that only DirectX games benefit from higher DPI's and that ET and OpenGL can't handle them. WRONG. That might have been the case in 2003 or 2004, (I'm not even sure if it was because I only started on ET in 2005) but not now. OpenGL and video drivers have long evolved to take advantage of DPI's EVEN in older OpenGL games, and there is NO hardcoded cap in ET's code to prevent the game from benefiting from higher DPI's.
The point about higher DPI's also magnifying eventual mistakes is a valid one, but then again, if you're a "pro", your "pro" precision should far compensate for the few mistakes you might make (after all, you're a "pro"!), so the higher the DPI the better (of course, up to a point where you feel comfortable).
I use 2000 DPI with 1.4 sensitivity at resolutions from 1024x768 to 1280x1024. At higher resolutions, keeping the same DPI, I'd have to increase sensitivity (by LOWERING the sensitivity Cvar) to compensate for the higher amount of pixels per inch. Without scripts, you can't play with much lower values than these and do the kind of stuff I do with the RG or my famous instant 180 degree turns without resorting to scripts (I don't use ANY, not even to change spawns - machos don't use scripts). And I can still own technoob tamere on a 1x1, him with an SMG and me with the rifle. Let's hope that he improves his play for the forthcoming NF 1x1 ladder.
Bottom line: you want your device to have the best/highest DPI rate possible, accompanied by a high USB polling rate. That was up to 500 readings per second on older Logitech mice like the MX518, the G5 and the G7, and is 1000 on most contemporary mice like my current G500. There's another myth here about the need of patches to reach 500 readings/sec on the USB ports - NOT TRUE (or maybe it was the case with the very first USB implementations). You can check the actual rate at which your mouse is being polled through the USB port with
this program. It works fine on XP 32 and 64, any service pack. I don't know if it works on VistaTrash or 7Garbage and don't care.
I used a G7 for years - basically a wireless G5, which was basically an MX518 with a laser sensor instead of an optical sensor and adjustable weight. These three are still the best mice ever for me, with the G7 being perfect if you could put up with changing batteries twice a day. Unfortunately, it also had a manufacturing defect (read "Logitech using crappy components") which caused the left mouse button to start double-clicking after 1 year or so, because of the low quality microswitches used. The same would probably happen to the right button if it were used with the same frequency as the left button.
You have been lectured. That means The Sacred Emperor has kindly shared an infinitesimal part of his infinite knowledge with you and won't engage in further discussions on this subject.
