We had our 1st local match allowing PCC's a week ago, and while I was skeptical about how this was going to affect the flow of the match, it had little impact. The folks at Custer Sportsman's club did an excellent job specifying a separate start position for PCC shooters (every stage had a pink dot spray painted on a wall that the PCC shooters aimed at for the start position). Sure, it took a few seconds longer for the PCC's to unload and show clear, but it had little impact.
PCC is the 1st division since Open/Limited to allow more than 10 rounds. Not only that, there are NO restrictions on mag length or capacity, and dots and comps are allowed. It's a very cheap way to try out what is essentially Open division with a rifle.