I own a pipe that has a 9mm and a savinelli with a 6mm. IMO, i havent noticed any difference. All i can say is that the 6mm can reduce gurgling (since there is a piece of cedar absorbing any moisture) and the 9mm has carbon rocks that can filter out the harmful carcinogenic particles. A lot of people claim that they will always smoke with filters so can they live a little longer and some claim that filters can reduce the flavor experience.
I havent noticed that from aromatics; maybe installing filters with orientals, Virginians, and English blends can be noticeable.
In my experience ive smoked with and without off and on (I smoke maybe once or twice every two weeks in a span of year). If you have a filter pipe i recommend smoking the filter for a month and the other w/o. I guess its just personal preference.
Example: People like smoking a cigar with a band and some do not.
-Junior Noobie
1-year experience
Own:
SG VF (8oz!)
Penzance (2 tins aging)
Scottish Cake Robert McConnell
Stonehaven
Bobs chocolate flake
W.O. Larsen Signature
Time out
Squadron Leader
Blue Note
Bella Vanilla by CAO
Da Vinci
Pipes:
Savinelli 606 Rusticated (6mm)
Peterson (K&P System Shape 3 Family)
Sandra (9mm)
Two MM corn cobs; bent and straight Diplomats
MISC: i prefer smoking with friends, playing chess, and cafes.