I have eight of the AUVA 70s under my Von Schweikert Endeavor SE speakers. Before I had the Von Schweikerts, I had eight IsoAcoustic Gaias under my previous towers, which were about the same size and weight.
This may not be helpful, because I've never done any critical listening comparisons between the AUVAs and the spikes that came with my speakers. However, I have never heard better soundstage/imaging from any system - in my home, in my audiophile friends' homes, at dealers' showrooms, or at audio shows - than I hear from my combination.
My floor is carpet over concrete, so I use the AUVAs' spiking system. It is practical and convenient, providing the speakers with a solid and stable foundation, yet also allowing me to make minor toe-in adjustments relatively easily. The AUVA feet with spikes make it easier to adjust speaker positioning than the Gaia feet, which sat on IsoAcoustics' spiked "cups."
There are obviously many reviews online from people who have made more detailed comparisons. All I can say is that the AUVA 70s have become an integral part of my VSA speakers, and I haven't felt any motivation to change them or try anything else.
