there is some interesting info on the dark core boards here
http://www.wakeworld.com/MB/Discus/messages/1/665382.html?1233712195 and it definitely sounds that these boards are better all around... assuming 2009 materials are not much different than 2008
i have not ridden any ronix boards but it is my personal opinion that the difference between a begginer or learning board and a pro board (that does not say beginner to advanced on the specs) is 3-5 sets of wakeboarding.
another question to ask yourself is what style do you have or expect to achieve? for example, the the Covin is a faster board as it is a continuous rocker and the One is a threestage board. maybe you already considered this and is why you are leaning toward the One shape?
wait for a couple more opinions to solidify your choice of course
and another thread about dark core here
http://www.wakeworld.com/MB/Discus/messages/1/661317.html?1233634624
(Message edited by wakerider111 on February 03, 2009)