I got a Logitech G5 mouse as a late Christmas present, so here's a long ass review I wrote out of boredom. You'll be in a catatonic stupor by the time you're done reading it.
This mouse is actually the second generation of G5 laser mice on the market. It's apparently been somewhat upgraded from the first generation, which only had one thumb button and a different surface texture design. Other than that I'm not sure if anything's changed.
Same generic Logitech packaging as any other mouse they make.
There's actually a fair few more doohickies included here than any other mouse I've purchased. You've got your mouse, a case of weights, the weight cartridge, and a driver disc. At first I thought the 50 dollar price tag was a bit much compared to what my old Mx518 cost, but from the looks of things I think I was mistaken.
Inside the rather nicely designed padded case are a large collection of weights of either 1.7 or 4.5 grams a piece. I'm not really sure where Logitech came up with a number like 1.7 grams, but there you have it. These small cylindrical weights are to be arranged in a little clear blue cartridge with eight available slots. This offers an insane amount of customization, and honestly I think I'd be happier if there were something like three selectable weights instead of this little case and with sixteen miniscule weights to be lost amongst the clutter on my desk. I highly doubt even a "professional gamer" would notice the difference if they'd used a simplified system, but that's just me.
Once the weights are inside the little cartridge, you slide it into a little slot on the bottom of the mouse that holds it in place with a plastic tab. I'm actually not too thrilled with any part of this mechanism. I considered the last Logitech mouse I had, an Mx518, to be damn near indestructible. You wouldn't believe the amount of abuse that thing stood up to, and from its exterior condition it has no right to be operational. I believe its structural integrity stemmed from Logitech's use of very high quality plastics. While the mouse appears to be constructed the same way with the G5, the quality of this plastic slot is highly questionable. It lends a rattling noise to the mouse if you shake it around, and the weight cartridge will actually pop out by itself if you're too rough with it. That doesn't scream of unrivaled durability. In fact, I think Logitech only included this feature to give people a viable reason to upgrade.
The cord is a substantial upgrade from any other I've seen. It's coated with some kind of durable fabric material that lends a ropey feel to it. This also makes it extremely stiff and pliable, so once you've unwrapped the cord it won't snake itself back up into a tangle. If you're choosing to go wired, you should do it the right way.
The texture atop the G5 is a departure from the norm for me. Whereas my Mx518 was slick, this has a kind of papery scale-like feel to it. It's one of those neat coatings you have to feel to appreciate. The black sides of the mouse also have a grainy coating on them. That's good, because the rubber coating on my Mx518 wore out and started peeling. This new surface actually seems to absorb the sweat on your hands a bit, so instead of getting all slippery it simply improves the grip. The DPI buttons are positioned differently than on my old mouse, so that takes a bit of getting used to. I consider the old button setup more intuitive. The DPI indicator is cool too, though I'd never look at it while in use.
The scroll wheel now has a very annoying side-press button feature which makes pressing the center button quite a chore. Half the time you hit these side-press buttons it's an accident, so I consider them useless. Unfortunately, the addition of this feature required the hole around the scroll wheel to be widened for movement. The very thing that caused problems with my Mx518 was that dirt and dust got jammed in the scroll wheel and caused erratic scrolling behavior. A bigger hole will just promote this.
The G5 has these newfangled Polytetraoverlycomplicatedname feet on it, and it really does glide smooth as silk. I'm using a Black Knight XH mouse pad, and I hardly notice the difference between its surface and my fake woodgrain desktop. The tracking of the new "gaming grade" laser eye is probably a vast technical improvement over the old optical system, but in the real world I can't notice a bit of difference.
I didn't have to install any software for this mouse to work, just plugged it in and everything worked. That was a relief to me, because I absolutely hate software like the included SetPoint to be running in the background.
Overall, what you've got here is a really great Logitech mouse with a couple new features over older, less costly models. I couldn't recommend that anyone upgrade from a functional 518 or 510, but if you're currently working on a crappy old generic optical mouse, it's well worth it to spend the extra ten or fifteen bucks over older models... just as long as you can put up with some slight rattling.