I have both Valhalla and SPM (just sold the SPM) and, in MY system with MY room and based on MY tatses, the Valhalla KILLED the SPM and it wasn't subtle. You might also look at Silversmith cables which are great at a lower price (although different sounding than the Valhalla). Is it overkill? Maybe, but it made MORE of a differnce than almost any other (not all) equipment upgrades I have made.
I had a rep from a speaker manufacturer at my home last Friday, who had been here about two months ago. The only change in my system from his previous visit was the Valhalla in for the SPM. He sat down, and after 1 cut asked me "What the hell did you do to your system?" I asked why. He saids "It sounds tremendous - way different, more fleshed out and just "THERE"!" He was also amazed at the lack of smearing and timbral purity of the instruments in large scale classical pieces. I told him what the change was and he said he now wants to look into using Valhallas in their demo room at the factory.
Is it the best cable out there? Who knows, that is for others to decide in their systems. In mine, it is a sure winner.