My 2 centsworth: Sobell, Lowden, Ralph Bown, Nick Benjamin, all owned by outstanding exponents of Celtish open tuning virtuosity. Not cheap!!

I had my Nick Benjamin JOM in open D minor the other day and someone remarked that it sounded fantastic, but other tunings drew no comments.

What is best? Depends on all sorts of preferences, so good for one person is not good for another. But I'd say in general, that as alterered tunings are usually dropped down from standard, that a longer scale with heavier strings will work better.