I don't think it's stay dry but I don't use a liner with it most of the time, if Austin is looking a little red then I will but most of the time I don't bother. I think it's down to personal choice and how tough your babies skin is.
Lucas has to have a fleece liner on with anything except pockets. He has very sensitive skin though. Not sure whether OBV is supposed to be stay dry or not but I would guess so as loads of things are topped with it.