I believe they are a very good pipe. They are UK based, so we do not see that many over here, although they are available here. Many folks here use Micron, Two Brothers, D&D, Yosh, etc.
You might pop over to the UK board and ask some opinions there, as they prolly have more of a base of folks using them.
http://www.bikersoracle.com/blackbird/forum/index.php