I bought this keyboard off eBay for a very reasonable price, and I am very happy with my purchase.
I bought this board as a replacement for my laptop keyboard which was getting worn up by intensive gaming. I knew that I wanted some quality, hence my decision to go with Logitech.
At first, I didn't want to go with something wireless, since I thought that I would suffer from wireless transmission lag and problems of the such, but after having trouble finding USB wired keyboard, I decided that it couldn't be that bad and I bought it anyways. Turns out that I was totally wrong about transmission lag, since it didn't affect me anyhow, might that be in normal tasks like writing documents or in hardcore gaming where I punch the living daylights out of the W,A,S,D shift and control keys.
The keyboard has an overall very good feel to it. The keyboard can be used in two different stances, like pretty much all other keyboards, that is with the legs up or down. Your choice of stance is personal preference, but unlike some IBM keyboards which are jacked at extreme angles when put on the legs, the slim profile of the LX 300 makes it pretty low, even when with the legs up. For additional comfort, a wrist rest is also included in the box, which I prefer not using.
I thought that the key layout and response on this keyboard was just great. The keys have a nice angle to them, and all is positioned right where it should be for easy access. Its the Delete-Home-End-PGUp-PGDown block that needs the most getting used to, but I like the way that the accent is put on the Delete key, which I tend to use more often. The keys have a nice springyness and noise to them, being crisp on initial press with a comfortable amount of overtravel, without being too hard to press, in fact I could even add that they are lighter on initial press then my laptop's keyboard. The keys do just a bit of lateral wiggle, but not any more than any keyboard that I have used.
The shortcut keys are also very well placed, and all of the them are customizable with the Logitech Setpoint software, which controls both keyboard and mouse. All of the F keys have alternate functions on them, which for me isn't really practical but for some that are more used to office work is wonderful. The back and forward keys are a wonderful touch for power-browsers, and they work perfectly in Internet Explorer and Firefox. I have not tested them in any other browser.
I have never used the mouse, but I personally wouldn't trust it for any hardcore gaming where you need more DPI.
As for previous comments on battery life, I have not run into those problems yet: I have had this keyboard for about 4 to 5 months, I use my computer 4 hours plus per day and have not changed the batteries a single time.
Logitech says it is spill proof, but being too broke to buy another one, I have not tested that either, although the many little holes in it's underside suggest that it would stand up very well to a spill.
This might be just my unit, but the mouse does not seem to work when only the USB port is plugged. I have not tried it yet with PS/2.
From what I have heard, it will work with Linux but the media keys may or may not work.