Dell PSU's are very high quality units. Their computers go through hours of testing and such before they're shipped out.
You may laugh @ Dells standard 350w PSU but I'd be willing to bet a large sum it'd handle a load better than your Ultra X-Connect, PP MGuire.
They pair the PSU with the PC's config. A Celeron with some slow DDR and one hard drive and no dedicated graphics card doesn't NEED more than 150w.
Sony VAIO CS110E 14.1" :: Core 2 Duo T5800
3GB DDR2-800 :: 250GB HDD :: Intel Media Accelerator
Gateway GT4024 :: Intel Pentium D 805 :: 1GB DDR2-667
700GB of Storage :: ATi Xpess200 :: Sharp AQUOS 32" 720p