My EVision is my only instrument for use while driving and so far I'm not really looking for more.
Months ago, I took my instruments apart and removed the seemingly Victorian wrapped wire on bimetallic strip fuel and water temperature gauge from the middle of my dashboard. Phil came over and wielded his Dremel-like tool to make the EVision fit into the space left behind and I'm very pleased with the result. My EVision is my only instrument and so far I'm not really looking for more. It measures Volts, Amps, Watts, Amp-hours, State of Charge, Wh/km, km/h, km To Empty, Time To Full, Temperature, Balance (the difference in voltage between the two halves of the battery). I find the most useful display is state of charge on the bar graph, and Volts & Amps on the numeric displays. The Wh/km is averaged over what feels like 20 or 30 sections - long enough that it's hard to hold a steady state, and short enough that you can't repeat the same trip in opposite directions. I haven't fooled with the miles to empty feature yet.
My biggest complaint is there are too many options. You use a remote knob to scroll between no less than 20 different combinations, but there is no way to reduce this to a manageable number. I set up 5 and repeated them 4 times, and then after I connected the speed pulse, I added Wh/km. I foolishly only inserted this page once (the configuration software is very painful to use) so I often loose it and have to scroll. It also needs a trip average Wh/km display.
The EVision has a PWM output to drive a fuel gauge. Since I removed my fuel gauge, I plan to ask Victor if it can be reprogrammed to drive a tachometer, or build a voltage to frequency converter. Since I only plan on using one gear, motor revs are directly proportional to road speed, so I don't need the tach. State of charge displayed on the tach would free the bar graph on the EVision itself for something else. I think I'd put battery current on the bar graph and I don't know what I'd do with the spare numeric readout.