I think it's probably tough for the PSU companies to get them reviewed.
I doubt many (if any) sites that do PSU reviews actually pay their reviewers. I know neither site I review for does!
All my review related income comes from selling PSUs. Given that there is about the same amount of time and energy put into reviewing a $350 1275W unit (which was excellent) as there is time and energy put into reviewing a $45 430W unit (which was okish), I think you can figure out why you don't see many reviews of lower end units!
Especially given that with no warranty you're in very good shape if you can sell the unit for 50-66% of it's initial cost, minus the $15 shipping costs you.
My total time spent photographing, testing (actively, any burn in time is not included), taking apart, putting back together and writing about a PSU is between four and six hours. Some units (the CM Silent Pro Hybrid 1300W for instance) take longer still due to extra features (fan controller, etc.) that need testing.
Let us do some math here!
We'll use five hours as a total time spent number, it's about right for me most of the time.
That $45 430w unit will probably sell for around $30 shipped, it fits in a $10 flat rate box. $20 profit.
Divide by five and I worked for $4/hour. Not great. No tips here either.
The $350 unit sold for $200 and fit in a $15 box, so $185 profit. Divide again and we have $37/hour.
(In reality that review took longer too, we'll ignore that)
On a more realistic note there is an "average" high end unit, $200 new.
Sells for $100-150, fits in a $15 box. That gives $17 to $27/hour. Not bad.
I think you can figure out why nobody reviews entry level units!
I'd like to do more low wattage units despite it being an economic disaster, for exactly the reasons given above. Most people don't need top end stuff, and if I could identify a $30 unit that was actually worth buying I'd probably be hailed as a hero and become famous. Of course, I'd have made $2/hour for the review.
The other tricky thing with that is that few manufacturers will send those units, some of them know what will happen and hence don't send them (be suspicious of a unit with no reviews!), others are made by companies that don't care about reviews or figure they can't get their units reviewed. Or companies that don't want to spend the $15 (per reviewer!) shipping units off for review!
As a final note, if any of you have a PSU you would like to see reviewed let me know and I'll try to get the ball rolling. If all else fails and it's cheap you can simply buy the thing and send it to me, I'll review it. Or send me the money to buy it and review it, either way. Given the above rundown of how much I get paid I think you'll understand that I'll want to sell the unit afterwards! Assuming, of course, that it doesn't explode.