I believe most Bjarne pipes are unfiltered, if memory serves me correctly. Quality? I cant speak from first hand experience, but reviews all across the board have been mostly positive. Of course, for the price that you could get a Bjarne, you could spend another 10-20 dollars and get yourself a nice Savinelli which in my opinion are some of the best smokers for the money.
I picked one up off of P&C a few months ago. Its a good pipe for the money. It didn't come with a filter or stinger. I don't know if it is designed to take a filter. I never use a filter so I never pay much attention to filter specs. But I am happy with my purchase. I would pick up another.
My first (and so far only) briar is a Bjarne Viking Classic Red Polished Apple. It came with pre-carb coating, no filter and no stinger. It also claims to have a vulcanite stem (but I am still too new to know for sure what vulcanite feels like vs acrylic). I did a cleaning to remove any excess stain and ended up dissolving part of the pre-carb coating. So I removed the rest of the coating, let it rest for 2 days and just smoked my first bowl out of it last night. The drilling is spot on and the draw seems about perfect. Other have complained about restricted draw and I will agree after a cob it feels restricted, but it seemed to smoke quite well for a first bowl and has me excited to get more briars. Mine is a bent shape, so it does not want to pass a pipe cleaner for me, but it also seems to stay relatively dry so I am not sure that is a detraction. One thing I will mention is that my stem seems very tight, but I plan to try a little graphite on there and am sure it will be fine once it has been taken apart a few times. Mine is also a pretty standard 3/4" x 1-1/2" chamber, but some of the Bjarnes and Tsuges have smallish bowls, so check the sizing in the specs.