Advice... Galaxy Nexus vs. HTC One S

Htc-one-s-vs-samsung-galaxy-nexus_medium

I'm on T-Mobile's kickass $30 a month Unlimited web and text, 100 min plan. Now, my current phone is a Dell Venue Pro and it's on it's last legs. I would love to upgrade to a HSPA+ device with Android 4.0+, a higher res screen, a killer camera, wifi calling, very slim, and generally fast. Unfortunately, that device is a mix between these two above. The One S has the Wifi calling native, plus it's sleeker, faster and the screen looks nicer to me. The Nexus brings Android 4.1, it's huge screen and fantastic support and clean slate of zero bloat.
I'm buying off contract, so hellllp!!