My two cents ; I'm listening to ARC Ref 6 (not yet been wiling to pay the price to update to SE) feeding ARC Ref 75SE amp running 4 KT 150s. My Ref 6 came with a heavy solid aluminum remote. Can't imagine the Ref 6SE having a plastic remote but I cannot say for sure. The thick plastic top on the Ref 6 is quite sturdy, provides excellent heat dissipation and I love looking at the tubes and the very pleasing layout of the internal parts. I have heard that the 6SE has an even thicker plastic top. A couple years ago I stopped being able to listen to my system because the music kept distracting me. So while some extra cash would encourage some upgrades, basically I am quite satisfied where I am now. I see that the Ref 6 is showing up used or as new dealer stock being sold off for around 10K, then the upgrade to 6SE is 3K so one could end up with a Ref 6SE for 14K.
There is nothing overly sweet or syrupy from my system, maybe slightly warm, and with great tight bass punch. I had wanted and got naturalness with nothing added, nothing taken away by the electronics (in so far as possible). This is what I have. The only drawback is that I am at the mercy of the quality of the source material as what goes in from my front end is what I get. My system does not mask or improve poor recordings. (Though, oddly, I have never heard youtubes being so listenable as now.) The sound I get is unquestionably resolving and detailed without sweetness - and natural rather than noticeably
analytical.
I listen to classic & progressive rock, small group jazz both vocal & instrumental, classical (prefer chamber music), some electronica, some world music - India, Indonesia, eastern Europe, middle Eastern - and all kinds of eclectic stuff depending on my mood. I listen for realism and emotional response. For me, at least for now, ARC does the job. (Of course front end and wires also matter.)
Unfortunately I am not familiar with BAT, it was too long ago that I demoed some of their gear for me to make any comment. Best advice is always to listen to your options - preferably in your system in your room - because everyone has different tastes in sound reproduction, different ears, different cerebral decoding and different opinions of what is good or better . . . on not.