I don't have any experience with Eonon, but I used an AVIN unit that was real similar with no issues other than a few quirks that is to be expected from aftermarket units. I think I paid about the same for my unit. Maybe it's just the expectation from a 300-500 unit and a $2000+ audio upgrade direct from BMW.

Are the Eonons, Dynavins and Avin units that much different?