ARS makes their own capacitors as far as I'm aware. But years ago, their tubes were rebranded JJ. That's what Bogner used to use.
As far as evidence goes for why I like them more? I dunno... I've tried JJ, F&T, ARS, Nichicon, Panasonic, Sprague, Philips, and a bunch of others. I think modern snap-in electrolytics from Panasonic and Epcos are world class and technically better, smaller, cheaper, longer-lasting, and more reliable than anything else. However they don't really fit in tube amps unless we're talking PCBs that were designed (spaced) specifically for them. So for dual-section electrolytic cans that are meant to replace vintage parts, ARS are the best ones currently available IMO. They sound better than F&T and JJ to my ears, they are reliable, and affordable. What more do you want?
Bogner uses them. Marshall uses them. A bunch of other amp companies have used and still use ARS caps.