There are a few different thread that talk about Pat's Easy Change. If you do a search and type in Pat's Easy Change or Quick Hitch you will probably get plenty of information. There are several different styles of quick connect hitches. Pat's is nice for those folks who use a Post Hole Digger as it is the only quick hitch I know of that works with a PHD. Pat's also works well for people who do not have standardized implements, again, Pat's works with differnent brands/sizes of cat 1 equipment. If you have standardized implements and/or rarely use a PHD, then you might want to look at the other brands such as the Speeco unit, as those types are more convenient than Pat's if they will work for you.
I have Pat's and love it. . . it was my only viable choice because of my implements.