If I had to pick one of them I would go with the coolermaster. Note the copper heat transfer pad. The stock intel one isnt bad though. Dont try to overclock much more then 5 % with either of them though.
I used a similar heat sink to this at one point, same design different company. Results were moderatly better then the stock cooler. When choosing a air cooler important things to look for are Copper (more is usually better) Fan RPMs/ how many CFMs (cubic feet per minute) the fan can push. Im a big fan of the ZALMAN CNPS series for air cooling. weather your looking to get the most bang for your buck or your looking to get the most epic cooling I would suggest checking out http://www.frozencpu.com/
Ive been using their info for years in combination with newegg.com and obviously tomshardware.com