6th Generation AirPort Time Capsule or Fifth Generation Extreme + Express Combo?

[culb0743]

I live in a 2 bedroom apartment; my internet connection is fiber at 50 Mbps. Currently, I pull 30 Mbps down, standing one foot away from my existing non-Apple router, which is single band 802.11n. About fifteen feet away and through two walls the speed drops to 20 Mbps. I looking to make the most out of the 50 Mbps I'm paying for and was sold on the 2013 Time Capsule (or possibly APExt), that was until I realized that I could get a fifth generation AirPort Extreme plus an Express at the same cost. I have no 802.11 a/c devices at the moment and don't foresee acquiring any in the near future. Possibly the iPhone 5s, but it would be the only a/c capable device on the network. I'm asking for advice from users who've replaced fifth generation AP hardware with sixth. Aside from future proofing, does the sixth generation offer much to 802.11n devices? My network currently services, a MacBook Pro Retina 15, iPhone 4 & 4S, iPod Touch 4th, iPad 3, and iPad 4. Does anyone have a similar usage profile using a fifth generation AirPort Extreme and Express combo? Does it leave anything to be desired? Thanks in advance to all who respond.