I switched a few years ago from MBP to ThinkPads running Ubuntu (with Gnome). It's been an overall improvement for sure, and there are very few things I miss (iTerm2 is the big one; there's no Linux terminal emulator that has all the advanced features I loved in iTerm2 like incremental search/highlight/copy. Gnome terminal with tmux is...acceptable). And of course it's much cheaper; on both computers (P51 and X1 Extreme) I paid about 2/3 what I would have paid for a MBP.

The big downside is battery life. On both the ThinkPads I've had, the battery life has been roughly 4-6 hours, despite my attempts to improve it with Powertop and/or TLP, and despite keeping the external graphics card shut down. I find that pretty painful; I like to work outside most of the day when the weather's decent, and now I have to be meticulous about plugging in whenever I go inside for a bit. If it weren't for having it charge up over lunch, there's no way it would make it through my day.

Some folks seem to get better battery life with some ThinkPads running Linux, but I haven't been able to pull it off. In fairness, I do a fair amount of CPU-heavy work -- but I was doing the same kind of work on MBP, and the battery life was much better.