OP I have no experience with LEPA, but I have had a few Coolmax PSUs. I have an OLD v-600 that is over 7 years old and still kinda works (though its not consistent enough to use any more) and the new ZX-600 model that I replaced it with. These are inexpensive and you can often get a dud. The first ZX-600 i got was DOA. I doubt that they can actually get up to the rated Watts of 600, but at the amount of power you are using I doubt that would matter. Honestly my brother has a v-600 as well and its running his web browser/htpc just fine. They are OK. If you want to OC or do anything extreme i wouldn't use them. I think the "500W" model is actually alright as well. Just know that unless its 80 plus it probably won't get its rated power and even then maybe not. (I dont have a meter to test mine)
On a side note I've always gotten my rebates from Coolmax
Takes em a long time, but it was a check in hand and not a card.