I used to have a 3.5G Deathadder (same as the Black edition, just not glowy) which I killed in a modding attempt (tried to change the blue LED's for red, ended up breaking off a ribbon cable
) and as they were out of stock I replaced it with the 2013 edition which I still use.
Only major difference between them physically is the texture of the plastic and the side rubber grips. The 2013 has a rougher texture while the 3.5G is very smooth, it was weird moving between them but IMO it doesn't make that much of a difference. Rubber grips, I dont have sweaty hands so its not an issue for me, but I can see how it could be a dealbreaker for someone who is. Shape and size of the mice are identical, perfect for my hybrid palm-claw grip. The 3.5G scroll wheel definitely has more pronounced notches in it than the 2013, but they are still there, its not a free-wheel.
The Synapse driver is annoying to use admittedly, I also thought it was pretty ridiculous how I needed an account to use a mouse driver. Though once you put up with it for 10 minutes and everything's set and done updating, you can pretty much ignore it for ever after. Occasionally it will pop up asking to update itself, but its a mouse driver, so you can just close it
The 2013 has a pointlessly higher DPI sensor, which doesn't change anything as I still use the 1600 DPI setting I figured out on my old Deathadder.