I like the rotabroach style much better. The only bad part about the Blair cutters is they are brittle and around $9 each or more. Lately I've been using another annular cutter, from Harbor Freight of all places, and it works excellent. Around $4 with a two sided cutter and adjustable tension centering pin. Much less brittle and the cutter even works with a couple teeth broken off.
HF cutter bit