i'm using a mouseman optical so i feel ya
i'm gonna upgrade someday to a logitech mx510 when i can get a a new blue one for less than 30 (counting shipping)... i've decided to go corded again - over the weight of batteries mostly... plus their cheaper w/ tails
i'm keeping my eyes open to the mx700/1000 though for a good deal
you're doing the smart thing by trying to hold em in your hand - but if you really don't like anything out there (though i can assure you you'll get used to most things like this over time - its like trying a new frame style for your glasses or something), and don't think you'll like it later after buying it... then why not stick with what you've got ?
if you want to upgrade coz it LOOKS like you've been using it the last ten years, consider dissasembling/cleaning/giving it a paint job
