There's a similar post somewhere on the forum, but here goes.
I have a Marvel conversion that I use for Bullseye matches. Very accurate, but the slide does not lock back on the last shot. Uses Colt .22 Conversion mags. You can get decent after markets from MetalForm. I shoot std velocity target ammo out of mine with no problems.
Advantage Arms is making a similar unit where the slide will lock back.
I also have a Colt Conversion Unit (hard to find now and expensive). It has a floating chamber to approximate the recoil of a std .45 ACP. Requires the use of plated ammo or else the floating chamber will lead up.
I've heard good and bad on the Ciener conversions. They have been around quite a while and seem to work.
No experience with the Kimber unit, but they look like they should work just fine. They use a different magazine IIRC.
I was considering a conversion for a while but found that I could buy a Ruger MkIII, 22/45 as cheap or less than a good quality conversion kit and I don't have to convert one of my 1911's. It has the same "grip angle" but is a little thinner in the grip and with a different trigger set up. Maybe a worthwhile consideration. Good Luck.