They are both decent power supplies for the money. I just got the bp550 a few weeks ago and it is excellent (running 4gb of g skill ram, athlon II x3, and HD 4850). It was also on sale for $44.99 though. The reasons I think it is a better choice are: it is semi modular and the cables have sheathing on them.
With the promo code and free shipping it makes the EA650 a really good deal and i would go for it over the BP550, the Earthwatts series is better than the Basiq series so i would pick the EA650 over the BP550 even though the Basiq is modular.