I had initially seen the aeroforce gauge and was very highly debating on purchasing that, but i just wasn't quite committed to installing a pillar cluster or the HUD pod yet.
That being said, when i do decide to go that path, i more than likely will decide to get one.
anyways for reference the scangauge in addition to being an obdII scanner also servers as a trip computer computing:
» Maximum Speed
» Average Speed
» Maximum Coolant Temperature
» Maximum RPM
» Driving Time
» Driving Distance
» Fuel Used
» Trip Fuel Economy
» Distance to Empty
» Time to Empty
» Fuel to Empty
as well as gauge readings of:
» Fuel Economy
» Fuel Rate
» Battery Voltage
» Coolant Temperature
» Intake Air Temperature
» Engine Speed (RPM)
» Vehicle speed (MPH and KM/H)
» Manifold Pressure
» Engine Load
» Throttle Position
» Ignition Timing
» Open/Closed Loop
i have only added a few of the xgauges (you enter a few codes in one of the options menus to enable said gauge) but thus far the following can be added:
» Horsepower
» Short and Long Term Fuel Trim (4 banks each) <- ?? no clue
» O2 sensor values
» Elapsed Time Since Engine Start
» Knock Retard
» Barometer V6
» Barometer V8
» A/F Ratio
» Remaining Oil Life
» Engine Torque
» Trans Fluid Temperature
I'm pretty sure there are others not necessarily listed, but mostly to due with the trip computer (ie: cost per mile gauge)
all basically taken from scangauge.com