My main rig right now is 11" macbook air (mid 2013) with a 1.7GHz i7 and 8GB ram.
It’s not a ‘workhorse’ in the traditional sense (ok, or at all), but after ripping the combine bits out of BlockParty, it can drive a 40 minute set without dropping frames.
I’m doing all of my DSP on an Universal Audio Apollo though, and I would suspect that I wouldn’t be able to run half as much in terms of effects as I do now on the CPU alone
On topic to the original post, I’ve been debating whether to upgrade to a Pro, or to switch to a ThinkPad, primarily because the cost of the hardware is so much lower. I’m on the fence about being stuck in Windows-or-Linux land, so it’s a tough call for me, but @inrascable, depending on what software you’re planning to run (or write), that might also be a consideration?