Have owned a Colt .22 conversion unit for many, many years. Great item, very accurate and reliable, if it's kept clean. The little floating chamber is prone to becoming gummed up with the waxy residue typical from most .22 lr loads. Once it's gummed up shooting is over until it's clean again. Not sure about other maker [Kimber etc] .22lr conversion kits].
About 5 yrs ago now I bought a GSG 1911 .22lr pistol & never really looked back. Very impressed with them for what they are. In fact, so impressed, I've since purchased a second. Another sidebar is I've found the GSG .22lr magazines can be used with my Colt .22 conversion unit. They function flawlessly. Very handy to know as real Colt .22lr conversion magazines are quite scarce & usually very expensive when found. [Again, not sure about using GSG .22lr mags in other .22 lr conversion kits for the 1911].
I've also owned a Browning 1911 .22lr.... the scaled down version of a full sized 1911. I'll echo what was said above "Nice gun but way too small". I no longer own mine for that exact reason.