John, I have tried these blends but so far, I am preferring the Basil Rathbone inspired #515. Tasting that rum flavor while still tasting the Virginas coming through is a very pleasant smoke.
I have both filtered and unfiltered pipes. I predominantly smoke with a filter but I only use the balsa 9mm filters on my pipes that take 9mm. They do not restrict the draw like the barrel filters do. I have several Petersons that take 9mm filters and the balsas work very well.
I have several of both pipes and only have had 3 pipes that had drilling issues and they were Savinellis. I must have gotten them all. My pipe shop made good on them so no harm done. I have an equal number of Savs and Petersons and love them both.