If you're considering the Pro's - which you shouldn't as they're getting pretty up there in terms of age - You might as well get the nanoHD's as they have newer, better, hardware.

Also, where are you seeing an AP Lite for $170? This listing on Amazon is $80. If you're worried about coverage or throughput issues, you can just scale up the deployment of the Lite's as needed.

Edit... Yeah I wasn't thinking when I asked that question; of course that's for two.