There is a few ways to approach your question. LGA 1150 and LGA 1155 are the socket that the processor uses, but it doesn't mean a specific one (like a car that can take different engines, but you don't say which one). On each socket, there are three main lineups - i3 (budget, lower performance), i5 (mid end, what I like to call the 'gaming' processors, and i7 (the higher performing).
Now, each lineup is targeted at different people:
The i3 being low power, and cheaper, for light gaming to internet browsing.
The i5 being mid range, performs well, 'gaming' oriented.
The i7, high end, higher performance, the video rendering/virtualization processor.
Beside the lineups, there are the two different current generations - Ivy Bridges (1155) and Haswell (1150).
Haswell performs about 5-7% better at the same clock speed (the number that is measured in Gigahertz (GHz)), as they use some newer technologies.
IB performs alittle bit worse, but they run cooler and are bit cheaper.
When you compare two processors, in the same lineup, from either generation, you'll find that the Haswell one will perform abit better, so it's really up to you on what you want.
Do you want to save abit of money, and have a processor that runs cooler, in exchange for some performance?
Or do you want higher performance, newer technology, and 'future proofing' (I say that in quotes as nothing is future proof), in expense for temperatures and price?