I also built a power supply using a simular switching P/S module that I ordered from Newark. I built it on one of these prototyping boards.
It has been running for about 2 months now on the Pi I use as a music player. While I didn't have a scope to look at the output my voltmeter shows 2~3mv of AC and the voltage is steady at 5.02 volts. It also bypasses the polyfuse so there is no voltage drop there. I couldn't use the existing placment on the proto board for the regulator because the pinout is different and the traces on this board are very thin so I don't reccomend this board. One day when I figure out how to do some programming on the Pi I intend to add a Pic chip to this board and turn it into a battery backup using 8 AA ni-cads or a 12v gell cell. The hurdle for me will be writing a program on the Pi that monitors an I/o pin and issues the shutdown command when the pin goes low and pulls down another pin right before the shutdown is finished. The Pic chip will monitor the incomming DC voltage and switch to battery when it fails. I'd also like to add a couple of switches to turn on/off the Pi much like a PC does.