I tried the 2006 Competition, which is technically a semi-dry top with a neo neck gasket. However, there is a band of solid rubber (not latex?) against the neck that makes the seal quite solid. In testing it, I rolled a dozen times, exited and thrashed around like a dolphin twice, and nothing at all came through the neck. I was wearing a 100 wt fleece sweatshirt underneath, and the only part that got wet was the bottom -- that's probably because I did not roll it up away from the tunnel.
The only issue is that the neo neck did get a bit damp inside, but there was no flowing water.
'Taint perfect, however, and I have a couple of suggestions for IR. The velcro cinch tabs on the outer waistband point backwards; it they pointed forwards, they would be easier to cinch; there's not nearly as much leverage pulling backwards around the hip. The inner tunnel might benefit from being a bit loose with a cord cinch, like NRS; without that, there is still a bit of a "dance" getting the inner tunnel fully down over your butt. The wrists could use a velcro cinch on the coverings; I had to peel the covers back to get at the gaskets for flattening and sealing, which was a bit of a nuisance. (I think velcro wrists are a feature on some other, more expensive IR dry tops.)
But generally it's a very nice product. The outer fabric sheds water like gel coat; the seam taping looks top-notch; the feel for paddling is very comfy and it is overall quite light.