If it is problem with PSU under warranty than you don't bother with some strange boxes and take that to seller right away. Otherwise, if 23 bucks is low cost for you, than OK. Just that multimeter is ten times more usefull piece of equipment… Also, it was already mentioned but testing PSU with no load may be invalid method. Testing loaded PSU gives you much more informations.
I actually use both if necessary but find the Thermaltake tester is the quickest method requiring no knowledge to use. Of course testing a PSU loaded give more information but as a quick test a simple tester can't be beaten.
The main problem still remains - it may very well not find problem even if there is one. I also personally tend to remove the root of problem before it even occurs, which is mostly replacing bad capacitor brands before the caps themselfs go bad.
It may or may not find a problem but if you're trying to rule out basic faults they're ideal. Excellent advice, lets get everyone replacing capacitors in their PSUs, but only those you deem crap.
Sure, good brands and model lines going bad are extremely rare. Crap brands take for at least 2/3 problems with PSUs.
I still use the multimeter method. The most important being the 8/4-pin CPU pins and the standby voltages.
