I imagined the display was "VITAL" .. 2 weeks with the Kenevo and I was "why do you need a display?" .. you get used to knowing what mode you're in - sort of like a car with what gear you're in (if you stick shift). If you're ever not sure, just mode up or down, if there's no beep then you were already in either eco or turbo (depending if you went up or down).
If you use mission control or blevo, both have screens you can customise to see anything you can possibly imagine. Just use a phone mount. The information's interesting, especially early on when you're trying to work out when the power's being used, what you range is and so on. In time you kind of know all that anyway somehow ... from experience I guess