The HCG-520 managed to exhibit a fairly good performance in almost all of our tests. The PSU's outdated, but cheap to implemented, group regulated design holds it back in our CL1 test and general voltage regulation on the minor rails was on the loose side. On the other hand voltage regulation at +12V is very tight and ripple/noise suppression on all rails is excellent. In addition the use of high quality capacitors promises increased reliability and long life span while the cooling fan has also increased MTBF (Mean Time Between Failures) thanks to its ball bearing. If you combine all above with the relatively low retail price then this Antec HCG-520 looks like a very good deal.
Bottom line, if you are on a tight budget, don't have a problem with non-modular PSUs and your power needs are covered by a 520W PSU then you should definitely take a look at HCG-520 since it offers decent performance, is backed by a three year warranty and comes at a good price.