A couple of thoughts... Over the past year I have transitioned from triathlons to more crossfit, at the same time Mrs LD has moved to doing Bodyrock everyday. If you don't know what it is then Google bodyrock.tv (moderately worksafe).
The two biggest observations are that a) I have so much more time back in my life and b)much, much more effective at training the big climbing muscles (lats etc. not so much finger strength)
But the counter intuitive part has been that keeping weight down is easier than when doing long distance on the swim/bike/run.
I guess it depends what other climbing training you are doing. If you've been doing plenty of intense bouldering, campus and finger-boarding already and have reached a plateau after a couple of years, then starting some contrasting functional upper-body/core strength exercises on the rings, free weights etc may well help you find some more gains. If you haven't reached a plateau with the climbing-specific exs, then I'd spend the time at the wall, doing these.
Crossfit seems to be a brand of circuit training gym rather than actually being a unique set of exercises. I like the exercises, but I don't need the whole 'community' thing. As for Bodyrock.tv - circuits with added silicone! She never seems to aim for low reps/max intensity.