Firstly, I was very impressed by the speed with which this product was delivered. Ordered late on 14th, arrived Royal Mail 9:00am 17th. That's what I call service.
After hacking my way through the virtually burglar proof plastic packaging I fitted the supplied battery (nice touch), shoved the wireless receiver into the USB of a DELL 1525 with UBUNTU 8.10 loaded, and had the arrow whizzing around the screen in seconds. End Track Pad Misery!
All of the buttons work, the scroll wheel scrolls. I haven't even attempted to download the 'extra features' from Logitech as they're billed as MS and MAC specific. Might give it a try later - you never know.
Unsurprisingly therefore some of the more arcane features of the mouse don't work, such as the side-to-side feature of the scroll wheel or zooming in or out, but so what. (1 star deducted nonetheless!).
All in all, a really good product from a really good supplier, and I would say it could be ordered by Penguin lovers with confidence, despite the OS not being specifically mentioned in any of the blurb.