A/F/R gauge for tuning

But is it useful or not?
Ever try to read the voltage on the output side of the instrument voltage regulator?
Would a digital gage be useful?
Would a 0-100 V scale on an analog meter be useful?
How 'bout a 0 to 8 Volt scale?

Again it comes down to what a person is going to use it for. Then sampling rate, readablity, ability to add on to it, will quickly narrow down the hardware which will fit your goals.
Readability is a biggie for me. I can imagine what a pain it'd be trying to read a small analog wideband gauge while driving. I've used Innovate and AEM units and have been happy with both.