I don't see it as quite so black-and-white, which is why I posted the question. The silicone forms to the contour of the hatch/hatch lip, but doesn't 'squish' like the neoprene does. What happens if the lid doesn't sit down exacly as it did when the gasket was formed? Why don't they use silicone seals on car doors? Because car doors will sag a bit over time -- but the flexible rubber seals allow for the variation and form a seal wherever the door meets sheet metal.

Basically, a silicone seal is a hard-surface-to-surface fit and a neoprene seal is a force-a-squishy-surface-to-conform fit. Neither can be theorized as better, but maybe through other people's experience we can find out emperically which is better.

Dean

> I have no experience w/ either, but just think about it - you can get a
> perfect seal w/ silicone - one that conforms to all the little ups and
> downs of your hatch lip (you can leave it rough) - one that gets thin or
> thick if you've screwed up the hatch location a bit - one that any dumbass
> with a caulk gun can do in his sleep - one that can even squeeze in any
> gaps - one that could even conform to a runner or internal lip - one
> that's easy to repair - one thats quickern hell - and with hardly any care
> at all you can get it perectly flush also!!!

> how easy and perfect do you want it?

> -mick