I know its late but just for future reference, the 8150 is binned a little higher and that means possibly better and higher overclocking. If youre wanting to overclock as high as possible, it might be worth going with the 8150. If youre not wanting to do hardcore overclocking, then the 8120 is the way to go.
I bought my 8150 just for this reason, so I could have a little more fun overclocking and so far its paid off. Im at 4.4 on STOCK voltage! Im only limited right now by my Hyper 212+. I could do 4.5 and game just fine but my temps get over 61C with Intel Burn Test and I thats over my own self imposed limit. Im saving up for a H100 and then Ill be able to really crank on this thing and am hoping for 4.8 maybe.