486 will be discontinued at the end of the year but nevertheless I'm going to study for it and try to pass the
test. I heard many people say that 486 is a very valuable test (even if a bit outdated as it refers to an old version of UML).
Preparing for an exam that is going to be canceled in a short time might sound stupid but I'm really interested in analysis and design so I don't care much about the test but rather the contents of the exam.
Besides I guess it's rather easy to prepare for 633 and 634 or other OOAD tests (like OMG's) once you master the 486 contents. What I don't feel like is to study for a particular product (Rational
Rose, in the case of 635) because I don't want to tie myself with a vendor, but this is a matter of personal choice.
I'm not sure I answered your question, just my 2 cents...
Claudio