Here is what Hobie has posted: "Islands experiencing rudder problems. Some users have had the rudder kick up making steering difficult; others have experienced loose gudgeon screws, and some have had worn or broken steering lines."
None of those problems is any real reason for concern, and quoting them tells me you are being somewhat misinformed. Gudgeon screws, for example are on the new model not the older ones.
What's are your location, experience and sailing intentions? Hard to really answer your ? without knowing this.
Generally, weather and budget should guide your decision. If you are going to sail in heavy wind/waves I would opt for the new system, even if it means waiting for a used one. Having a rudder pin break or the steering be overpowered in life-threatening scenario is the thing to focus on here. Those are more likely with the older rudder.
If you are doing casual sailing on inland waters, the older boats are more than adequate, when maintained properly. (Keep a supply of grey pins on hand and know how to change them quickly or how to steer with the rudder).
Without knowing more, I'd say go for it. You can always buy this one, learn the ropes, have some fun and sell it later to upgrade. Right?