What you have is two segments, the enthusiast and the mainstream.
Mainstream SandyBridge without the "K" denomination offer similar perfomance at less power use. They are not intended for OC, fair enough, this is not what we should be looking at. At this level the older 1156 and 1366 is better choice for enthusiast.
For enthusiast, you get a "K" series CPU that allows you to overclock beyond 4.3GHz on AIR. And uses less power to do so. And if the £250 suggested by TechRadar is true that's about right for that level of performance.