Cheap closed loop cooling systems are junk. I would be much more inclined to use a rock solid cooler like the 212 for a medium OC. Add another fan to the 212 and you will run just as cool as the H-50 with 100X more reliability.
the coolermaster is an overclocker favorite because it's great value for money, however it can get abit noisy when the fan is going @ full tilt. the h50 isn't any better and in somecases worse than top end air coolers in the same price range. i see newegg have the noctua nh-u12p on discount right now, and there are others too that would accoplish the the same while running nice & quiet. but sound level is personal perference. for a quick & easy oc of 4.3-4.4 with decent case airflow, the coolermaster should do the trick.