Has anyone had any experience with neoprene hatches? I saw one on a seaward kayak and thought it was pretty cool but I hesitate because I wonder how water-tight they are. Do they have to have a hard shell cover? Also they seem like they might be cumbersome to put on when it was cold. One upside though would be that a large rear hatch could be made pretty inexpensively and it would sit fairly flat to the deck. Anyone have any thoughts on these?

Also, has anyone seen a "Beckson" style hatch that is a large oval? I am trying to get away from using a VCP because of the weight and expense.