It looks like I won't be help here, because I switched from the MX1000 to the Performance MX, and I love the new mouse.

I used the MX1000 for something like 8 years (I went through a couple of them - the non-bluetooth versions). I loved it. I loved that it had a docking station for recharging, I loved the button layout and the general feel.

Eventually I decided on a couple of things: it was going to be tough to keep finding replacement MX1000's, and the more I thought about it that dock wasn't a good idea. When the mouse wasn't charging it was a bit of a vampire, and it was sitting on my desk collecting dust. And given the battery life, the dock was usually just sitting there doing nothing and taking up space.

So when my last MX1000 started acting up like yours did, I moved to the Performance MX just like you did. I also reacted badly to it, but I knew it was because I'd been using one mouse for so long. I felt the same way when I moved to the MX1000 from my previous beloved mouse (I think it was this one?). So I gave the MX a chance, and now I can't imagine going to another mouse (and I use a TON of mice).

I have mixed reactions to the button layout change. I really like the bottom thumb button because I can just rest on it. But I don't like losing those buttons in front of and behind the wheel, which I used to jump back and forth between articles in Google Reader.

Anyway, I recommend getting used to it. I've had my MX for over a year now, and I'm not bothered by the ergonomics at all. But you may feel differently. I don't really know of other mice to recommend, but GDGT is starting to be a decent place to check out collected reviews of gadgets. I'd skip down the the "All Mice" section where they just list them all by score. Perhaps the MX 518 might appeal?