I cannot believe that you’d like both in the same system
I went from Thiel CS1.6 to Vandersteen 2Ce Sig II to Thiel CS2.4SE. I’ve been increasingly happy at each stop. When I first got the 2.4s, the midrange had a "glassy" quality but otherwise were a step up from the Vandies. There was evidence that the previous owner overheated a couple of resistors. I replaced all the OEM sandcasts with Mills MRA-12s and that pretty much cleared up that issue. I have since completely replaced every passive part from the binding posts to the driver hookup wire. Now, I’m super happy and, other than bass extension and definition, hear them as nearly as good as the very best I’ve heard (Vandersteen 7, TAD Ref One, Vivid Giya, Avalon Ascent).
During my rebuild, I heard an opinion that Thiel’s practice of using 1 uF bypasses contributed to a "tizzyness". So, maybe that’s the cause of the claimed Thiel treble issue? According to this source, bypasses should either be 1% or less or all-in (eg, >25%).
Regardless, I liked Vandersteen and Thiel in my system/room.