My upgrade path on mice (that had actual NAMES) was:
MX1000 (lovely mouse, lasted me AGES - untill the cursor would suddenly start flying up into the upper right corne rof my screen after 20 mins of use) ->
G500 (also a nice mouse, however, I didn't quite like the feel of the grip on that mouse. Also, it was quite heavy. The sleeved cabling tore somewhat up and I had to keep it from further tearing with gaffer tape, which ended up being a major hassle) ->
Steelseries Sensei (not RAW... I like it. Always use it at the standard 5700 CPI while using one screen/not gaming at all. If I start using eyefinity, I'll boost it up to the 11400 CPI (which was hard to get used to, but I eventually nailed it). I dont like the deceleration/acceleration software, so I turned it off - it threw me off a LOT while aiming. The color and little picture display is just a gimmick. It's very, very light on my glass-plate mouse "pad" - feels like zero resistance between the glass plate and the mouse. The grip is not always optimal, when I start to do the claw grip (I'm usually using a palm grip) I cant quite get the right feel,as there' is no rubber or the like for the claw grip to latch onto (it's all painted plastic and with hours of use, the paint WILL start to tear off, leaving the ugly plastic color exposed.).)
Currently I'm debating which mouse I should get - the Sensei is a great mouse, but I really am wearing it down quickly (also, the claw grip issue is a pain on the sensei).
I'm thinking of going back to cordless, but I don't want a mouse with "11+ programmable buttons" - It's just a distraction to me, as i don't play MMO's at all. It just needs to be cordless, lightweight and at least 5700 CPI. (On that note - any ideas would be appreciated