Purchased my Paragon stencils here. Have not applied them yet, but know Wotto has and he was very happy with them.
http://www.pinballpal.com/products/stencil/
I believe Mark CLAYTON (owner of pinballpal) was/is quite ill unfortunately. Although he makes great stencils, I don't know whether he is back on his feet producing yet. I would suggest to email them and wait for a reply before ordering.
I have had some troubling results from other manufacturers of stencils (****NOT RETROPIN / GAVIN** *) from an overseas company. The material they used was almost as sticky as mylar and lifted the base coat clean off the cabinet. I have read / heard stories of another O/S manufacturer whereby the differing colour layers do not even come close to matching.
Marty is right. Mark Clayton (PinballPal) won't be fulfilling orders for quite some time. I tried buying Playboy and a few other licensed stencils, but I found out he was going to be offline for a while.
I have not used Gavin's yet, but I have my Pro football stencils ready to apply. He has all the Gottlieb stuff on his website.
Be VERY VERY careful with other Bally stencil kits out of the USA on Ebay. They are CRAP and you will basically lose time and money. The other option is to make your own, which I've done several times, but it is HOURS of work, and only useful for simple lines of shapes - ideal for EMs (except Pro Football).