After a quick look, the MSRP of the PowerX-550 looks rather high for a non-modular Bronze unit with a capacity of 550 W, but I was, after I finished all the tests and had the necessary data to make the performance-per-dollar chart, surprised to see the PSU take third place. And I, amazingly enough, used the MSRP price; it is usually higher than the retail one. This PSU will be a very good deal for someone that is on a tight budget, especially if the price drops below 60 bucks.
Performance-wise, the small Cougar surely isn't a record breaker, but it still has good voltage regulation on all rails—excellent on the 5V rail—and its ripple suppression is really good. It also doesn't have a problem delivering its full power, even at higher than 40°C and features a nice painting job, which, however, is prone to scratches, and its compact dimensions will ensure an easy installation.
The negatives I spotted are the performance of its 3.3V rail at dynamic loads, the lower than 16 ms hold-up time (something common in budget units), some incomplete solder joints on the PCB that holds the first part of the transient filtering stage (which, however, didn't cause any problems during all the tests I ran), and, finally, the existence of only one Japanese cap while there is a misleading reference to more "Japanese caps" on the box. Such inaccurate product descriptions surely don't look good to us reviewers and experienced users.

To wrap up, I think that the fresh PowerX-550 is a PSU worth buying if you are on a tight budget, especially if you find it for a lower price than its MSRP, which will most likely be the case. This time, the performance-per-dollar chart spoke, so I couldn't but give this unit our budget award.