If my option was limited to just the 2 I'd pick the G402. But honestly you should consider the wired version of the G403 if you're considering any Logitech vs a Deathadder
also if mouse feet is an issue check and see if someone else makes them
http://www.hyperglide.net/?hg=paypal-na
hyperglide makes pretty good mouse feet, and they cover a large range of gaming mice both old and new, only downside it can take a week or 2 for the feet to get to you at least in NA.
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MarxistThe mouse feet are indeed very small, and they will wear down after 2-3 years, I assume it would be worse on a "control" type mouse pad surface that is more abrasive. The easiest replacement is to experiment with different kinds of tape - duct tape and masking tape give you more control, whereas scotch, packing, or electric tape gives you more glide. You don't have to do that straight away, but after a few years you'll want to, especially if you have to take the mouse apart to clean it (you have to take the feet off to accomplish this).
PTFE mouse tape can be got for about $5-15 depending on thickness and amount, also heating up the mouse feet before removing them makes the process a lot easier and typically you can put them back in place with no problem.
MarxistEventually your m1 will die due to wear, just sand down the plunger with a nail file and it will work again - like new.
This is the point where you should consider getting a new mouse lol.
MarxistThe Synapse software they want you to use is not very stable, and I would recommend against having it turn on on start up if you aren't using an SSD because it likes to hang on start up a lot and lag up your computer's startup routine - at least for me, perhaps it's because I was using a legacy mouse.
Synapse is a nightmare, most people setup their mouse and uninstall it...
MarxistThe only real flaw in the design of the mouse though, is the very smooth sides of the mouse, if you play for an exceedingly long time it gets pretty slippery - I used fine grit sandpaper to correct this so that it would be a little more rough. The downside is it collects dirt better when it's no longer smooth so you end up cleaning the mouse more.
Most mice end up being like this, my G400s after a few years of use has a really smoothed out/slippery area where the thumb usually is