I'm thinking about buying this new system for my Nacra 6.0 which I keep on the beach. Are those little parts reliable in such a corrosive, sandy environment? 
I've heard of people replacing these systems with stock hobie systems because of reliability issues.
hearsay however.
You should check out how appropriate they are for beach launching. My understanding is they are either up... no steerage... or locked down. You can't go half way with them..
This is never good for any rudder system on the market but we all cheat!
Good luck
Mark
Dotan rudders do have three positions: Up, down, and stuck half-way in-between. In the latter position you must grab the blade and push/pull it past the pivot-point.
The weak link is the adjustable upper gudgeon, which is held in place by four small screws and has the tendency to rip off. If you're lucky, it rips off when you're beaching the boat. If it rips off while you're flying a hull, the forces on the rudder cause it to twist about parrallel to the water's surface. This means the lower gudgeon (which is very stout) twists the bolts that mount it to the hull right through the transom of your boat.
I've busted 2 or 3 upper gudgeons on my G-Cat 5.7M, my friend broke 2 on his P18-2. He's switched to the TheMightyHobie18 system and now that I've re-glassed the inside of my transoms, I'll be doing the same.
I think they would be excellent for dingys: Optimists, Lasers, etc.
I have been using Dotan system on my TheMightyHobie18 for 5 years.
This kick-up rudder is easy to use and I must say it operates perfectly.
Aluminium upper and lower castings deteriorated in my old rudder. Every part and even blade were dangling here and there.
As to Dotan I have never experienced any probs with gudgeons. In theory it rips off when you clash with any obstacle moving backwards, but such strike is hardly imaginable.
And while beaching maybe it is worth to kick up the rudder and trim the sails? 
Rob.
Dotan Maritime Industries continuously improves rudder quality, we never stop at what has been accomplished. Rudder system is our main and only direction, so fundamental enhancement research isn't a rare event to us.
During latest (14.04.2004 - 20.04.2004) durability tests of rudder boxes designed from the start of year 2003, we conducted a special "upper-gudgeon" test. After pushing the load on the rudder blade to the limit (absolute side pressure simulation model of the water on the rudder blade), till complete rudder box destruction, we failed to break the upper gudgeon.
Hereby we are confident to state that upper gudgeon can be broken only after hitting an underwater obstacle on backward motion . The solidity of the upper gudgeon is rationally optimized to save the rudder blade from such heavy backward motion hits caused by large surging breakers in shallow water.
Happy sailing!