Sure, basically I felt the barts in the Pentabuzz tended to stifle both the singing character and the upper mids (the thup sound as your fingers release a string). So I did a bit of research and decided on Alembic Aviators and pretty much paid through the nose for them. In hindsight, I would have gone custom instead because you could probably mount any flat response PJ set and get the same results. The East pre has been on a few of my instruments. It's a clear sweet sounding preamp which doesn't sound too brittle. Nice combo with the Pentabuzz and it gives me that all important control over the mids.
On stage with the GK RB700 1x15 combo I used to have, I could get a gentle feedback going with the mids and it was like playing with a sustainer. Just a gorgeous sound...the aural equivalent of having warm chocolate dripped into each ear hole.
Does your Hexabuzz have soap bars? I remember Shockwave looking into getting replacement soapbars for his Pentabuzz. Andy at Wizard said he thought they were too narrow to produce a decent sensing field so couldn't build them to be a direct replacement. Might be something worth thinking about if you look into replacements. Just check yours are made for a 6 string and not a 5.