I would say go for scdjws because its not based on some specific product like it is for IBM.
The current exam is definetely outdated but its still used in a lot of applications. So, it won't be a total waste of time doing it.
Besides, the exam objectives are pretty broad and so you can learn a lot from
doing the current exam.
If you are not in a hurry to give this exam, then wait for a few months becoz
Sun microsystems is going to release the latest scdjws exam soon.
They have already developed the
objectives for the latest exam.
In my opinion, you can start preparing for that. It sure is huge.
SCJP 5.0, SCWCD 1.4, SCBCD 5.0, SCDJWS 1.4 & 5.0, SCSNI, ICSD for XML, SCEA 5 , ACE: Flex 3.0 and Air, ACE : Flex 4.0