Having heard the Proac 3.8s briefly, and never the VR5 but am very familiar with the rest of the line, I would say the VR5 will offer lifelike slam, bass, detail and openness while the Proac will not be quite as open aor offer the bass, but should offer a more refined top end. Again, take my comments lightly as I have never A/Bed those exact models, but am going on my experiences with the rest of the line.