I'm using a 2105/16 macbook pro with the retina display at work. If I was going to buy a macbook for myself, i'd hunt one down, as I love the keyboard, it handles development really well and lets me do linux type things without needing to jump through burning hoops of death like windows would in some instances. I'd thus recommend that if you want Mac, but don't want to splurge on a new one. Disadvantage is that you don't know what problems might be lurking etc etc etc. However, that model still has nice things like the magsafe power connector, a few usb ports and some thunderbolt ports, so more than enough connectivity, plus, it'll run 2 external monitors, which is a bonus.
Otherwise, if you're not bothered about it being a Mac, just take the cash and buy a solid windows based laptop. For the money you can buy real killer machines that'll do everything you need. If you're not tied to Mac, it's what I'd do.