It's really simple:
Socket 1155 is at the end of it's lifecycle, there will probably never be another processor for it. On the other hand socket 1150 which comes with new processors in June is at the start of it's lifecycle. It doesn't take rocket surgeon to see which one is better for future proofing if purchase isn't required now and it can't wait few months.
Buying used five years old tech is pretty bad idea unless it's cheaper than sixpack.