What's MacVim give you? I never got the point. Everything I've seen also existed in the terminal with a few simple vimrc config. Mouse/trackpad, clipboard integration, OSX commands.
MacVim also works with PeepOpen, which was just a jaw-dropping upgrade from tab-completing all my file paths from the project root. It practically reads my mind.
I'm thinking I will give FuzzyFinder a try soonish, though, since it would also work on Linux.
Also it's particularly difficult to get Solarized setup in a terminal using 256 colors rather than manually resetting the 16 colors of your terminal to custom values.
If you have a sane terminal, vim works fine with 256 color support. A lot of people on OSX use iTerm 2 which I hear has fine 256 color support. I just use gnome-terminal on Linux that's had support forever and dropped solarized since the maintainer is not interested in making any setup work besides gVim/MacVim it seems.
As an aside, I wish someone would write a Windows version of vim as good as MacVim. (Yes, I also wish I was talented enough to do it myself.)