I've owned the VSi-55 and the RWA Sig 30, not the 30.2. Of these two I liked the ARC better. It had great power, a really deep 3D soundstage and solid build quality. I found with my setup it wasn't as transparent as I wanted--only complaint. People tell me I need to go a few steps up the ARC line to get the transparency I want. Some day I just might.
The RWA is a great little amp but in the end I just didn't listen to as much music. A friend of mine suggested that maybe battery wasn't the way for me to go. Sounds weird but it lacked a certain energy, almost too calm. Not dry but no bloom at all. I wouldn't get in to battery gear again without an extended audition.
You should take these thoughts lightly because so much is system dependent and there are many folks connected to ears that love both of these. If resale matters, ARC has much better resale value.