I think most of us who went to the Konis came from the Ford shocks. It would be very interesting to know on my exact RV what the difference is between the Koni FSD and the Bilstein HD. Pricey for trial and changes..
I went with the Konis for reasons as Phil Nichols said in his post. As you have probably read, I'm very happy with them, they improve the driving experience greatly over the Ford shocks on a light 24' motorhome. Mostly based on control, but that is what I'm tuned to (focused) on this. Others have said the ride is much better and it very well could be.
Maybe call Henderson's Line Up Grant's Pass Oregon they may have experience with both shocks.
I found the control of the Ford shocks to be grossly inadequate. If that is your concern the Bilstein HDs could be a perfect fit. I chose the Konis because I didn't want any chance of wrecking the ride quality (or even slightly worse)..and I can say they give much better control with equal or better ride quality.