I believe this is an excellent CPU. It runs with no problem. I have a couple of additional comments to make, especially concerning some comments in other reviews. By the way, I used this to replace an i7-920 (which also required a new motherboard because it uses a different socket).
1. Although this CPU is supposedly not able to be overclocked (except for turbo mode), I find that is easily overclocked. My Asus P8Z11-V Deluxe motherboard (and its utilities) will automatically overclock it to about 4.22 G. It runs there 24 hours a day with no problems or instability. Of course, it won't overclock as much as the i7-1770K.
2. Concerning using the Intel CPU cooler that came with it: I used that at the beginning because I needed to get a different backplate for my CoolerMaster V8 CPU cooler. It did work, but was hot. With the V8 installed it runs more than 15 C cooler (at full load,(running folding at home with SMP (using 6 or 8 cores) and 2 GPUs) than with the original Intel cooler. So, if you overclock it and run it hard, I would recommend getting an after-market CPU cooler even though it will run somewhat OK with the original Intel cooler.