i use a razer deathadder myself. while i do not like razer synapse i would not say it has caused any problems for me. i just wish it was like the older days of just drivers instead of an application that wants to load settings to the cloud and update itself. for the record i've used both the driver and synapse.
i've tried mmo mice before (i found out i did not like them) and had tried out the g600, naga and naga hex. the naga and g600 felt like they had way too many buttons and any convenience was removed by not being able to press the right one. the hex has a place to put your finger on the side but i kept pushing the buttons instead when i lifted the mouse. you could probably use them in the manner they are intended but they will require quite a bit of training yourself to do so.
i was pleasantly suprised by the button layout on the logitech proteus. while having more buttons than normal but less than an mmo mouse it was easy to find the locations with your fingers while gaming. i ended up just going back to the deathadder as i prefer that kind of scroll wheel and the proteus was not quite wide enough for me. other than those two things i thought the proteus was great.
for the record, i normally keymap to numpad for skills in mmo (i'm an arrow key user) or i use a gaming pad like the tartarus.