the electronic throttle on my 2008 flhx is very slow at reacting. I passed a pickup on the freeway the other day and the throttle is very slow to react when you twist it..It should not be that slow.

 

I haven't had that problem with mine; my problem seems to be the high idle.
It seems the throttle by wire has many problems.

 

Check the touring section guys, lots of info, also use search function for FBW or ETC. I have an 08 RoadSlide and have no problems with Fly By Wire, I do'nt think there is many problems and it is very easy to reset. I know that some have done a simple reset procedure to reset idle. Like anything else on these bourds you will find alot of bitch'n, but very few confirmed problems with FBW. I think mine is better than the cable bikes I've had in the past.