Josh, when going through a MOAB swatch book the paper I liked the most was Somerset Museum Rag but for some reason I can't find it on Adorama's website in 24" rolls – the MOAB product number doesn't bring it up, either. (I need to order through Adorama as they are also able to ship inks to my part of the world when other companies can not). I liked the bright white Entrada so much however that I thought I'd give the Natural a try. The fact that it curls less because it's coated on both sides is an extra plus.
Regarding Hahnemuhle, I haven't experienced the quality control issues that you have but I'm certainly of the opinion that it's a little expensive compared to some of the competition.
I've had very mixed experienced with the Harman by Hahn MCS paper. Rolls have been perfect but cut sheets are a nightmare to use as the curl is insane out of the box. I'd end up wasting half a pack due to head strikes, etc.
As an aside, I first used MOAB products because at the time they were the only manufacturer making a quality double sided paper around 200gsm suitable for making high end artist books. Specifically, this was their Kayenta line of paper. They no longer make it but it's good they now make the Entrada rag in a lighter double sided weight to compensate.