So, I'm wondering, what are the differences between for example s3888, s3988, a3090, pmw3310 and 3366 in term of tracking/responsiveness/precision ?

I've personally tried s3888 (currently using this one in my aby 2k14), s3988 (the sensor inside the DA 2k13) and a3090 (zowie AM/FK). And I have to admit that I pretty much fail to find any major differences between these sensors. I mean, in my own experience, all of these sensors perform pretty much the same, I mean, similar tracking, similar responsiveness, similar precision. The only differences that I can feel are obviously the shapes of these mice as well as the different DPI settings. The rest... I just can't.

So that's why I'm asking you mice experts, can you explain to me the benefit of upgrading, for example, from 3888 to 3310 ? Is the tracking really different ? Is it more precise, or just marketing bullshit ?

My logic is that (in my humble opinion and from what I've experienced myself) all of these sensors are equally good, perform pretty much the same in term of tracking, and what differs between them are just the dpi customizations and the malfunction speed (also, in some cases, the software/driver). From what I understood (correct me if I'm wrong), recent/new [flawless] sensors like 3310 usually get higher malfunction speed than older ones. But the rest... I need your opinion/knowledge, so please, enlighten me :D