To me though, TAD is similar to Revel being the high end arm of a multi-national, broad-based company. TAD being owned by Pioneer, and Revel by Harmon. Is something lost when you have to answer to a boss in a corporate office 6000+ miles away? I don’t know.
The only tube amps i’ve heard pair well with the S5’s are Absolare & the CJ Gat & Art amps which both have solid drive. Though i’d love to hear how the Einstein or VTL mono's sound with the S5's. I think the Zanden amps would lack a bit of current to drive them to their full potential. My favorite gear for synergy as everyone knows is Vitus Sig series. I think Spectral and Devaliet are bad choices with Magico imho.