Are you talking about this one:
http://www.targus.com/us/productdetail.aspx?sku=AMW43US
Looks pretty good. Might try this one out.
I'd stay away from that. It's not the worst mouse I've used, but it leaves
a lot to be desired, and that's considering I got it new for less than $10. My biggest problems were with the side buttons, the drivers, and the optical scrolling (good idea in theory, didn't work very well in practice).
My desk mouse has been the Logitech MX Revolution for the past year and a half, which is nice because it has a charging station, so I just stick on there overnight every few weeks.
Since the Performance MX replaces the MX Revolution, I'd have to wholeheartedly recommend that. It'll be leaps and bounds better than the Targus. And considering it comes with eneloops (pretty much the best rechargeable batteries) and a charging cable, it's not really a big deal if it only lasts a couple of weeks. Just charge it overnight once in a while.
Even though you said no MS, I think my portable (sometimes desk) mouse deserves mention - the Microsoft Explorer Mini (which I think has also been replaced by another mouse). It feels really good in the hand, and it has a great tracking system. Oh yeah, and it's less than $20. There are a few similar mice in that MS line (different sizes) that I think you could check out.