In Gaming i would say the intel one is better.
But in Video Rendering or Autocad. The FX-8120 might beat or perform similar to the i5.
If you are going AMD, i suggest you wait a bit for Piledriver (FX-8320). I think they will release it this month. It will use the current AM3+ socket.Youtube: AMD PILEDRIVER CPU PRE-ORDER PRICES LEAKED!