To me a well regulated 5 volt psu which can deliver the right amperage is equal to any other well regulated 5 volt psu which can deliver the right amperage.
I don't agree with this.
How well your psu work if you've got interference in your 220v/110v ?
How well your psu work if you've got some more amperage (for example, a spin up disk in the usb)
How well the voltage is stabilised, on charge and off charge ? (did you get 6v when you use it at 25% of it's capacity ?)
How well the voltage is regulated ?(did you get exactly 5.00v or 4.97 or 6.5 ?)
What if, in addition to your DC 5v/1A (for example) you've also got some 40khz ? (can be present with a switched-mode power supply. With a "simple" alim, it's really difficult to suppress completly the 50hz.)
Or if the capacitor isn't big enough and your voltage is always between 5.1 and 4.9 v, but never stable?
how well your psu react to external condition (voltage drop, or raise. heating trouble which can cause some deviation in an voltage/amperage/noise correction)
There is a reason why you can found 600W PC-psu at 40€, or 150€.
And when you have already lost two hard disk, and practically a motherboard, you think that a psu IS a main part of your pc.
(I think i've put more bucks in my PSU than in my memory (8Gb ECC))