ARC Ref 3 or Cary SLP05, both will work extremely well. Giving you a very open soundstage and excellent bass. I think that Cary is slightly warmer than the ARC. I have never heard the BAT's or VTL's.
I have the 3.6R's and have tried both the 501's and the 402 Mac's and never gotten good results. They are great amps which sound fantastic with other speakers, and I am not sure why, but they sounded muddled and weak with my system(s). I love the Cary MB500's that I have, and I have tried many amps with my Maggies. Then probably the Sanders Sound ESL amps (formerly Innersound). VTL amps sound sublime too. I love the previous generation of them, especially the aesthtics.