mech is much cheaper, but what would be better and why? any disadvantages of mech boost gauge?

 

I've never used anything but a mechanical boost gauge. They are reasonably priced, accurate and respond quickly to changes in the intake. Never realy considered an electric unit.

 

Electric is actually supposed to be more accurate than the mechanical one. Plus the electric has a boost recall on my AutoMeter one, along with a warning light. All nice features, but as you already know, its more expensive, so you end up paying for them and the accuracy.