Abruce. I have auditioned both extensively. To my ear the Proac is the superior speaker. The speakers have similar tonal characteristics, slightly to the warm side of neutral. Both image well and throw a huge soundstage. The midrange is very good on both models--liquid, articulate, refined. The Proac is a little more up front in the presentation than the VR5. Where the Proac exceeds the VR5 is in two areas: musicality and bass pitch/articulation. The Proac threads the music together better. Instrumental lines are more distinct within the whole. You find yourself being drawn into the music. With regard to the bass, the Proac wins hands down. Both speakers have awesome power--the VR5 may even have more authority. But in terms of playing the tune and following the bass line, the Proac is far superior. The VR5 (and other Von Schweikert models I have heard such as the VR4jr and the VR2) soften the attack and round off the edges of the bass in a way that I simply could not accept in a speaker of this price range. This is not a huge flaw but a noticable one which, for me, was a deal breaker. The Proac on the other hand has excellent pitch, PRAT and bass articulation.
Overall, both are very good speakers though the VR5 is not such a great value for the money. I would say the VR5 is more of an "audiophile" speaker and the Proac more of a "music lovers" speaker. Hope this helps.
BTW-For less money than both and better performance to boot check out the new Fried Studio 7. Simply a phenomenal speaker. Musical, powerful, dynamic, neutral. Really worth seeking out.