Why is that? Simply because you can return them?
Looking at reviews it seems the Klipsch has the highest. ML is still new I believe so no real reviews out there. The similar XL model rated really high which uses the same speakers I believe. At this point leaning towards one of these. Is it worth double the price to get the ML....not sure.
I rather enjoyed some of the ML Motion series speakers I heard with their folded tweeters. But I doubt those exact tweeters are being offered in a sound bar, especially, with 3 of them. So in that light, and my own bias of spending that much money on a sound bar, I'd knock out the ML, or at least wait until there's a discount available.
The others, yes, take advantage of the ability to return stuff. I hear Jeff Bezos made $55 Billion last year alone.... lol!