I was thinking about this only a few days ago -- pretty much ANYBODY who has an RT/10 should do whatever they can to score a hard top now. I've seen the other aftermarket tops and I believe the Mopar top is much better quality, even if it does weigh a friggin' ton and is ridiculously expensive.
Simply put, for all practical purposes the hard top converts your roadster into a regular car. Wind noise is virtually gone, and if you have a loud exhaust, it really helps on long trips.
Totally worth the money, and now that the Germans have stopped building the real Vipers, it won't be long before hard tops are either impossible to find or are commanding a real premium price...