This is not so much a conversion, as a swap of type of coilovers. The stock setup ARE coilovers, NOT struts. A strut is an integral part of the structure of the front end; I.E. they ARE the upper control arm. Struts also include the pivot point for the function of steering, and you MUST get an alignment after replacing struts, as the strut itself is integral to the alignment, and by disassembling it from the knuckle, you have changed the alignment setting. The only reasons you are seeing a difference in ride quality is A.) You replaced parts that had 60,000 + miles with new, B.) You have essentially re-tuned the suspension ride by selecting a spring with a different rate, and coilovers with different (and adjustable) dampening rates, which happen to be more to your liking.
It is entirely possible to get the factory coilovers that will ride as nice, simply spec out a spring rate you want, and spec out the valving the way you'd like. Ride quality is all about tuning the spring rate and dampener valving to the vehicle weight and suspension geometry.
The benefit to swapping to adjustable coilovers such as you have, rangermidtn, is adjustabilty, both in preload and ride height, and dampening rate. Plus, you have more travel from the ones you selected.
What I don't understand is why with lifting these vehicles, everyone goes all whacky because the factory coilovers appear similar to struts due to having that top bearing plate. Why does truxx spacer go IN coilovers requiring they be taken apart necessitating the use of a spring compressor??? Why not put a spacer between the top of the bearing plate and frame mount ("shock tower") and retain full travel of factory coilovers?
Don't get me wrong, I am not knocking your work in any way, I think you did an awesome job getting your vehicle the way you want it and attaining more flex!
I just want to make sure others don't think they need to go trough everything you did, just to get a better ride out of their rig.
I am actually planning a suspension mod to get a little lift if availability of everything works out: ProComp's new prorunner adjustable coilovers for F-150 and swap springs for lower rate and see if I can have them custom valved a little softer. I still need to get some measurements, but almost certain I can make 'em work, and for around $100 a piece, cheaper than factory replacement coilovers!