I'm looking in the refurb store. I'm thinking the 2.4 i7 would be awesome. I currently have a late 2013 2.6 GHz processor on my 13" rMBP
I had a 2.4 before jumping to the Touch Bar. It was a pretty solid machine. Honestly, my 3.1 i5 Touch Bar doesn't feel any faster..I just liked the touch bar and extra ports. If I had it to do again, I might have ended up sticking with the 2.4. Geekbench shows it just about the same performance as the Touchbar 3.1 (just under) and a good jump from the 2.0. I think it's a pretty good sweet spot for the 13's. It is also about the same as the base 15 for single core.