Iv'e been looking at a G703 to replace my EC2-B and noticed there is a new version coming this month, as soon as it releases there should be some really good deals on the previous (12k dpi) version.
Logitech is trying to go 100% proprietary. I wouldn't be surprised to see them license some mice switch, like having Romer-G mice switches in partnership with some switch maker like they already have with Omron. It makes sense to incorporate the HERO on this scale, ignoring the advantages it gives to wireless pointing devices they do take 'ownership'.
Some people like the 3366 tracking (or accuracy to be precise) more than the HERO, and Logitech claims the HERO to be 3-4 x times more accurate than the 3310 and on par with the 3366. To be picking on the 3310 you need to have some OCD.
In the end, when using a wired mouse, 3310 is, in my opinion, the baseline come to competitive play. You don’t need any better than a 3310. Wireless, well, you need a HERO.
TrueMove3, Owl Eye are all based on the 3360 IIRC. and the 3366 is a minor improvement over the 3360 and 3389 is again a whole other class. Not going into too much detail, but the improvements entail improved incremental DPI steps, improved IPS/polling/tracking speeds. When you have a good pad to track on, then there is no need to go over and above a 3310. 3360 is mostly the norm today.
I have only mentioned PMW’s, older Logitech’s still use the ADNS sensors and other like Razer use PMW which are all good switches, the 3095 have some inaccuracies when you track at higher speeds.
The HERO is based on the Mercury. The Mercury is still used in the G102/G203.
Anyhow. No person can bitch when he/she is using a 3310 unless he/she is tracking on something inadequate.
There will be people who would still want a G703 with a 3366 even though the HERO will mean less charging. The question is whether Logitech will continue to sell current G703 and brand the new model as the G703 HERO. Scratch that, see they will only keep the HERO, but I see the G403 is now only available with the HERO (and, cough, new switches).