I recently asked a question between PHP, ColdFusion, PERL, ASP, JSP, etc.
I'm wondering the same in terms of databases. I'm looking for a good comparison of unbiased, honest opinions. What is more stable? What might be more scalable? Which one is more powerful? What is easier to use? What’s the theoretical limits on each database? What are the benefits and or downfalls you might have all seen between them and why do you choose the database software of your choice?
I'll award the answer to whoever has the most thorough answer. (I'm most interested in Microsoft’s SQL vs MySQL vs Oracle vs PostgreSQL - however please don't limit your sharing of knowledge to these databases alone. What you might have to say about another database platform might be very interesting here too!)