You guys realize they've made nearly 11 million Pentastars. They may even be pushing 12 million by now. If a tiny, tiny percentage of them had a certain kind of problem, every shop in the country would say they see them all the time.
The vast, vast majority of Jeep owners in the clubs in which I participate will tell you the've had zero issues, and they've punished the hell out of them in extreme conditions. They love them. Even the most hard core folks.
My Dad was a GM engineer and got all the trade publications. They pretty much universally praised the Pentastar as one of the best production engines on the market, with a relatively low warranty claim rate and high reliability and long term durability.
Of all the engines you can buy right now, it is one of the safest bets. Rememer, too, it does not have direct injection, so no LSPI or fuel dilution issues. It is very easy on oil compared to its contemporaries with DI. Plus, it is one of the most versitile engines on the market. It works equally well in pickup trucks, sports cars, mini vans and Jeeps.