Since I am not overclocking (obviously) the stock cooler is fine.
Using a 3rd party cooler on a locked cpu is more preference thing. If you are going for a certain look then the plain plastic-like look of the stock cooler isn't going to do it for you more than likely. Noise tolerance is another factor for some people. Some people find the stock cooler runs too loud for them.
Both of these weren't really factors for me so I just used the stock cooler.