Seems like they had some issues early on, some with the 9mm but more so with the .45 auto…say 6-8 years ago. Most of the more recent posts and video reviews I’ve found would seem to give them positive marks. I believe they’re now on a 3rd generation design and the older guns can be retrofitted with the latest revisions.
I, like you, am interested in the takedown models and I really like the idea of having both 9mm and .45 auto. The though of having a PCC in .45 auto gives me a chubber. The caliber kits run around $200 and include the barrel, bolt, corresponding glock (or M&P, I think) mag well, magazine and other necessary accoutrements to do the swap.
One gripe was tearing the thing down for cleaning, apparently they’ve now add a quick release mechanism to the receiver extension to easily remove it for cleaning. I figured with that and the takedown barrel, cleaning would be fairly easy, requiring only the removal of the charging handle (much like the Ruger) to get the bolt out the back.