Truthfully, they really don't make that much difference. An unpinned barrel is almost as secure as a pinned one. Cylinders really don't NEED to be recessed, case heads are pretty strong nowadays. It's just that P&R revolvers are a product of a time when craftsmanship and attention to detail were more prevalent. Plus, they're just COOL.
Guess that's why I'm the P&R Fan.
Jim