Abel, I did the little test that you suggested. Since I only have SE+, I don't have the sus-vib patches you talk about. There may indeed be different tremolo speeds.
As for room info, I don't find any difference between orch and cham ER's, and ln listening to them "placed in their space" using Altiverb (Todd 10M ST 2 ST) a mono melody (orch) becoming div. (cham) using sus or legato articulations works for me. (just for the record, I do regularily work with real orchestras recording my orchestrations). But or course our individual perceptions vary.
I was surprised (and at first disappointed) to realize that the note lengths of the short notes (detache, short detache, stacc) are all longer (consistently through the range and velocities) in the Orch library than in the Cham library. In that sense you're right that there's a different "sound" (or feel) there. That would make some transitions rough, but paradoxially in the end, some even better, giving the reallife non-consistency of real players. So for me, I continue to think that Chamber samples make good div samples for Orch.
I went ahead a riged up (in Logic) a splitter, triggering Orch, Cham, & Solo articulations at the same time. This is something that we should be able to accomplish very easily in VI Pro. And I have to say that it sounds majestic. I played lines using 5 articulations (Sus, Legato, Stacc, Short detache, & Detache), panned a little differently, and the sound to my ears is much better than Orchestral alone. I had read about that here, but never done it. And the non-consistency of the short note lenghts here may prove to be positive. I can see myself using this trio rather than the full App Strings that I own any time. [B]