I've turned several pens from the Euca. Burl and love it. It's a good burl to fill voids on. I had one blow apart into a few pieces while I was drilling and was able to gather up the pieces and CA it back together and complete the pen with a failry large inlay area.
One thing...I'm not sure if it's a shadow in the photo or not, but it sort of looks like the pen didn't fully assemble. It looks as though your tubes may be protruding out past the wood leaving a small gap, (again could be a shadow). If this is the case, one thing I've started doing is once I get the blank round and the trimmed areas are cleaned up, I take the blank(s) off the lathe and use a very fine flat file to bring it all flush before finish turning.
I need to turn a few of these Sierra kits. They all look good.