In my opinion it depends on what you're looking for in the fish. P. ornatipinnis individuals can undoubtedly be the prettiest of the bichirs but quite a few of them either hide all day or become 'logs with fins'. P. delhezi is one of the best around in all regards BUT, in my personal opinion the best all-around bichir that combines a nice pattern and is generally the most active and out-going is Polypterus palmas polli. That's the one that would get my top vote.
-Joe