I have used the Chambers oil finish for most of my guns. I tried Permalyn once and I didn't get good results, but I think it was more my fault that the product's. I went back to Chambers oil finish.
I had a discovery about using the Chambers finish that you all might be interested in. I have always felt that it left the gun too glossy and I was looking for a way to reduce the glare of the finished gun. When I used rottenstone in oil I always managed to cut too deep and loose some stained wood. On my smoothbored gun I call Turk, after the last coat of finish was applied I waited until the finish felt dry to the touch but not completely hard and then rubbed the stock down with a scrap of wool blanket, like I do when browning a barrel. The result was a nice soft sheen. The advantage of this approach is that there is virtually zero risk of cutting through the finish to the stained wood, even the tops of the carving. It achieves the same result as rubbing down with rottenstone in oil but without the hazard of cutting too deep.
Best Regards,
JMC
John Cholin