Are you looking for experience with the efii "brand", or electronic fuel injection in general?
WARNING! Incorrect design and/or fabrication of aircraft and/or components may result in injury or death. Information presented in this post is based on my own experience - Reader has sole responsibility for determining accuracy or suitability for use.
Harmon Rocket II -SDS EFI - Flying
RV-8 - Flying
1940 Taylorcraft BL-65 -flying
1984 L39C - flyable, available for sale