No reason at all not to get the AC model unless you're getting a significant discount on the N.
Buying N now would be like getting a G router just as N came out. I did just that when I picked up an extra WRT-54GL because I'd become so comfortable with my old 54G; I started to regret that decision not too long afterward.
They're expensive, and there isn't a terribly huge benefit, but 802.11ac will be on nearly every mobile device shipped in the next year.
Personally, while my TP-Link router is only 450Mbps, I might grab a .ac end-point for my living room stuff, to cut down on the 2.4GHz noise in that area, and provide a more stable connection to all devices. It's that or a power-line networking pair, and I think that the power-line networking might be the riskier choice overall.
Going to have to visit my local retailers to see if they have anything good in stock worth trying, so that I can return it if it doesn't work- they're all pretty good about price matching