I've ridden all 4 and gone for the B&Ms.
Lost gravity is an interesting one, but not quite refined enough to be worthy of a vote here and whilst Silver Star is not my favourite B&M hyper, it is a lot better than a lot of people seem to give it credit for. Oz'Iris is unusual for an invert, slightly more free-flowing than the Batman clones and their ilk and generally delivers a lot more than some of the larger ones (Raptor excepted) as B&M generally played it too safe. Megafobia is good, but rarely great