Well, I was curious and since I have the Henle WTCII with the Schiff fingerings, and in the notes at the end the editor, Yo Tomita, supplies two variants of the BWV 872, along with a lengthy explanation of his or her reasons for editing the volume as such. And, to boot, in Fr, German, and Eng., so anyone can read. It's a pretty long entry under the variants for BWV 872, but I have not compared to the current state of scholarship.
I don't doubt the Bärenreiter and their publishing house following the Neue Bach-Asgabe tradition, but from what I can see in my hands, the Henle is up to date and more affordable, perhaps. I don't know the prices or how desirable the Schiff fingerings are, but the Henle is a recent edition. It sounds like the Bärenreiter is equally or more good.
Although, do I have to be the first person to suggest that one look at all the engravings and editions? Really, I still look at the Busoni editions for Bach WTCI and WTCII, to get some ideas. One should be looking at old, old editions at the library, or student editions and so forth....one must look at all of them and synthesize.
For a stupid example, I was unhappy with my LH after a number of months of not playing for various reasons, and I thought the Emaj fugue from WTCI would be good practice (along with the Scriabin Op. 67 no. 2) as an abstract exercise. You know, go back to the woodshed and do H.S. for a bit, as one does. Just scales and bouncing around with the LH: jazz stuff, you know, but isolated a bit.
It never occurred to me for a long time to do HS for the WTCI Emaj fugue, but I printed out a few sheets of Busoni's edition and voilà.
You should read it all, is my guess. Purchasing? Yeah, sure. I'd go with the latest Neue Bach Asgabe, but even though I don't agree with Schiff's fingerings in the latest Henle, with the caveat that I only read habitually through the 48, mostly not paying much attention: that's also a good edition. I have no idea about the latest WTCI from Henle: I only have an older Peters edition in print, plus a bunch of photocopies of different editions, and a lot of my own pencil marks and so forth.