I have heard the Bespoke Audio, over many hours, in my own system.
I wouldn't buy the Naim because it is too expensive and I don't really like the whole Naim image. It's not for me. I don't know which is more transparent, I doubt that either product has any meaningful advantage. As always, I could be quite wrong.
Incidentally, Lucy and Harry of Bespoke Audio are driving to Munich in Lucy's 1959 Morris Traveller, which she rebuilt herself. People going to Munich will be able to examine the product and chat to them. Judge for yourself.
Incidentally, as I've never spent more than £6000 cash on any item over 40 years, I'm not the 'target audience' for either product.
Finally read the Hi Fi News review. Goodness, how boring, a string of weary old clichés. Talk about going through the motions. But then, as has been pointed out, this stuff doesn't sell on reviews. The few people I know who spend really big money never read reviews.