The MCDBA credential continues to grow by size of certified population and in perceived value and presence in the workplace. Thus, it's a pretty good credential to have: one that's held its value recently better than MCSA/MCSE, in fact. As for comparing MCDBA or Oracle, it's like asking truck lovers if Chevy is better than Ford, or vice-versa. Oracle still dominates the market, but job opportunities and pay for OCPs and MCDBAs appear to be about on par. As for your final question: if you want to work in an environment where both SQL Server and Oracle are used, obtaining both certs will probably be helpful; otherwise, you can focus on the credential that puts you into the workplaces you favor most.
This was first published in December 2003