I need some interface advice

[Koshigaya]

Hey. I'm Looking for some insight before I go ahead with this purchase. I want to upgrade my audio setup, nothing fancy just looking for better sounding audio. The microphone I'm set on is the AT2020. As for the interface I'm stuck between a few. The first one I was looking at is the Behringer UM2. The other interface I was looking at is the Behringer XENYX 1002FX because it's only $3 more than the UM2 and it gives me a lot more to play around with. The price here confuses me, why is the UM2 so expensive if the Xenyx 1002FX offers more? Is there something I'm missing?

I was also looking at the Behringer Xenyx Q502USB because it's less expensive and has what I need. I really only need 1 microphone channel. But I was reading that the microphone input is Mono and not Stereo, and that it only supplies 15v phantom power instead of 45v.

I'm not sure which one to get.

Also does it really matter what cables I get? Can I get away with a pair of simple RCA cables?