LOL, I am a n00b. I wanted to say the Autometer read the correct 4-5psi.
Blitz - I was an importer/reseller of automotive gauges about 2-3 years ago when I was starting out. I imported from several companies products, one of which included Autogauge gauges and accessories.
The problem that I found with the gauges in China was the calibrations they did. Often they didnt sit on zero (differences in air pressures from mountains in China where manufactured comapred to sea side melbourne maybe??) and they did over read boost. Thats just my general personal experiance.
In the end, I think in a market like gauges where precision and accuracy plays a big role, as long as you are comparing two plain gauges (aka, not defi or some cool feature having one) a bigger price will more often than not result in a better product.
Having said all that, if you just use the one boost gauge for all your testing (like using only a single dyno) and are well below the limit of the engine internals boost wise, I dont see a reason for a more accurate gauge being needed, as long as you always only compare with yourself (I am sure that kinda makes sense)
PS - I paid $100 for my autometer boost gauge from Autobarn. More than happy and I know its pretty spot on