I don't know. It seems to me that SF demos aren't going through as much of a vetting process on these strings as they probably should. Or maybe it's just that they are rushing to get the libraries out and so don't have the time to get everything just so. Or the demo writers don't have enough time or the beta the demo writers are working with isn't fully operational. All sorts of things that can go wrong when you suddenly move up the time table for delivery, which it seems SF did in this case.
In any event, I'm going from my own experience with AR1V1, which I really quite like. On pre-order pricing, with all my various discounts, I think it's not unreasonable at the price I paid, and the cello is even less expensive. AR1V1 is one of the easiest string libraries I have to work with. Nothing very fussy about it, it sounds at least adequate on pretty much anything I throw at it (even the runs don't sound horrible to me, just not as credible as I might like), and it has it's own particular niche that is really quite stellar. (Despite the implicit marketing as a John Williams toolkit, it has more of a concert hall than cinematic attitude in my opinion.) And I can get a lot of different performances out of it by selecting a different legato, velocity, dynamic layer, and so forth. I'm also finding it plays well with libraries recorded in other venues and it can sound both like a medium sized orchestral section or a large symphonic section, so it has that going for it as well. In any case, it's already become the library I reach for first, if I just want to get something out and I don't want to fuss because as I said it's been rare for it to be less than adequate.