I honestly don't think that it is worth visiting. Definetely visit Disneyland, but you may not make the best use of your time by visiting DCA. There is just not much to do there. It has its cool rides, (Grizzly River Run, Soarin Over California and California Screamin) but other than that the choices are very small. It has other average rides, but who wants to spend a day going on average rides.
If it were up to me, I would visit Knotts Berry Farm. It is certainly a much better value, and I think that it is a superior park as well. Good coasters, rides for kids (what DCA doesn't have), and many other great rides (Perilous Plunge, Log Ride).
Have fun on your vacation regardless of what you choose!
-------------
"Clear, Dispatch"