I have a 22" (I think) mid 2010 iMac and it runs perfectly well for design work, especially now that I've upgraded the RAM to 12GB. I also have a non-retina MacBook Pro that I have as a back up or for when I'm in meetings or working out of a remote location. One of my friends uses his MBP for all his design work, but he has it set up to an external monitor so he's not working on a tiny screen.