After Gnome 3 and the abomination of wasted screen real estate that was Unity released I switched to using XFCE on Linux environments and haven't really found anything better since. It's so snappy even on crappy hardware and is customizable enough.
I agree - taskbar on the side is the best layout. It's very common on Macs and you can do it in Windows 10 now too.
The problem with Unity was that it was buggy as hell, and the launcher was really badly styled. Huge gaps between icons, the search filter was unusable, etc.
Weirdly enough I loved Gnome 2 but for whatever odd reason I prefer some of the other DE's out there. I use Budgie (on Ubuntu) at work though it has quirks, otherwise Gnome 3 is ok or I just go for KDE. It definitely felt like Gnome went from all these amazing customizations to being so limited though.
I was always a KDE 3 kinda guy. I tried TDE, which is to KDE 3 as Mate is to GNOME 2, and … boy, you really appreciate how the Mate project managed to keep everything good about GNOME 2 but modernise at the same time.