I listen to large-scale orchestral music much of the time, and have listened to both of the above.
Here goes: neither of these excellent speakers will give you a realistic rendition of Mahler 2 (Klemperer live, Barbirolli) or 5 (Barbirolli), let alone 8 (Horenstein). An approximation is possible, probably more so with the VA + "swarm" (i.e. 3 small subs), than with the SF: the latter are difficult soncially to pair with subs, I tried for a friend and the results were not stellar. Maybe using their own subs is the ticket -- but we didn't have those.
SF Strads: the sound is, subjectively, slightly on the warm side (probably a bump around 80-100Hz) and pleasantly mellow especially with strings (not surprisingly). I really like these speakers.
The VA are less sonically friendly and more user friendly (you position them for optimum bass reproduction and then angle the upper part. Subjectively they are less mellow (i.e. there is probably no upper bass- low mids bump) and the reproduction of detail is thereby enhanced. What this means for Mahler or Bruckner (to use your example) is that the orchestra will sound correct, i.e. you will easily perceive all the sonic cues including low-level details (as per the system's resolution). On their own, however, the VA sounded to me slightly thinner than the Strads; coupled with 2 subs (small SVS if I recall), however, the sonic result was major scale. A plausible approximation of an orchestra was now possible.
The ultimate choice is yours, obviously.
[Re subs: I wouldn't worry. Your room is big enough to accommodate 3 subs, so mating with the main spkrs is not a problem. Audiokinesis does this (inexpensively I might add) and they are members here at Agon.]