Look at it another way. Buy what you like. If your leaning towards lower jaws or vice versa you may just end up rehoming a bunch of fish.
That does make sense, I'm trying to find one that I don't like at this point. I watched a member on here's video, the ultimate bichir care guide. After the first time I watched it I wanted all UJ's, then I watched it again and all the LJ's. Decisions