Is Mavericks pretty much playing well with most software? Mavericks is what you get if you buy a laptop right now. Yosemite won't be my problem unless I wait a bunch longer to buy the MBP to replace my current mid-2010 MBP, whose screen is going kaput slowly (I usually upgrade every 5 years or so).
Things I expect to use: LR4 (to be upgraded to LR5 shortly, my old machine is still on 10.6.8 Snow Leopard), PS6 standalone, AutoPanoGiga 3.0, Nik collection v.2, Nebulosity 3 (an astro program), and SIgma Photo Pro 5.5 (does .x3f Foveon sensor files from the Sigma compact camera series). I am looking to try either Zerene Stacker or Helicon Focus, and maybe Capture One, DXO, Iridient Developer, Raw Therapee.