Hi Bob.
Zeiss, Pentax, & Takahashi are most popular among recent (or current, in Tak's case) premium .96 eyepieces. Other (rarer) premium 96ers include JSO, Goto, Nikon, Kowa. Any good example from one of these brands is worth full consideration, in my opinion. Most will have the "orthoscopic" label (whether traditional Abbe or not), but you'll find Kellners & other designs, too. The Pentax XPs, for example, are designed for eyepiece-projection astrophotography, but many folks swear by the 3.8mm XP as a great planetary eyepiece.
Actually, my early '90s Celestron 18mm Kellner is excellent, too.
I'd have absolutely no qualms or hesitation about buying a good example of a .96 orthoscopic or Kellner from any of the above brands, if the price is right.
A bit of trivia, as an aside: the Takahashi 5mm & 7.5mm LE eyepieces utilize negative/amplifying elements in a sub-diameter assembly *within* the 1.25-inch barrel. This assembly is, itself, housed in a .96-inch barrel. If one were so inclined, they could unscrew the 1.25-inch barrel and use either of these LEs in a .96 diagonal or focuser. I've not done this, nor do I suggest it. The sub-diameter barrel is black-anodized alloy and, I'm sure, more prone to scratching/gouging. Removing the 1.25-inch barrel also exposes threads which would be prone to damage, as well.
Best wishes.
-Dan
