Well, I just use whatever mouse I have whererever I am. I even adapted, well kind of, to a terribly old mouse I have in my house which i used for my PC for a few months before I found the Dell mouse which was a big improvement. I use a palm grip generally on whatever mouse I use and I haven't had to alter my grip on any other mice I've used, even on the terrible old mouse I used where I had to kind of bend my fingers to use it lol.
I know about mouse DPI but I don't know what exact number my Dell mouse is usually. It has 4 adjustable DPI settings on the mouse but I just set it to the 2nd highest as I can move the cursor around my 32inch display fast enough. I even chose the highest setting sometimes either for gaming or general use and it wasn't too bad so I don't know.
The DPI-slowing button, aka. 'sniper button', on the G502 isn't really a deal breaker or anything for me, as I rarely feel like I need to adjust DPI on the fly when doing anything, though I guess it might come in handy. I'm not able to just try any expensive mouse as stores in Australia rarely have the branded ones, and you can't just try out the ones they actually do sell. My only experience with branded mice was the DeathAdder 2013 a friend of mine uses in Programming/Networking class which felt good but it doesn't feel right for me, partly because I disliked the Razer logo.
I know about the other brands of mice but I'm leaning to the G502 mostly because it looks the best aesthetically, with the braided USB cable (which the Corsair K70 mechanical keyboard also has). I guess I'm not too bothered about whatever mouse I use as long as it's a wired mouse, but I guess I haven't had the luxury of owning an expensive branded mouse personally.
The Logitech G502 Proteus Core is $60, and the Steelseries, Razer, Roccat etc mice are more expensive, around the $100 range. The G502 seems the best but I dunno.