I can only comment on what I had and that was the Apex-i AVC-R. I have no complaints about it. It worked good and gave alot of good information to boot such as RPM, Throttle %, Speed, etc. It made it really easy to trouble shoot problems by having all those variables displayed for you. I've heard complaints about it not being easy to use, but I disagree. It did take a short time getting used to, 5-10 minutes0, but nothing that would have prevented me from buying it.