Htc First Future Proof?

So basically I'm going to switch company to At&T but that's not the important matter, whats important is the phone I'm gonna get, so I'm aware that many of you would like to recommend the GS4 or the HTC One, but right now 200 dollars isn't at my disposal, so i quickly turned my attention to a quirky little device known as the HTC First for 99 cents (assuming 2 year contract of course). I love the feel, the size and the display of the device, really love the stock android underneath, but what makes me uneasy is the specs, they aren't last year flagship caliber so I'm not sure if the performance will be Solid for the next 2 years or at least a year and a half. So is it that future proof? Will it be smooth for all the time I'm gonna have it? Should I forget about it and consider another phone? i would really love to know First owners Opinions.