With the increased attention Postgres is getting, many ask whether Postgres has the same features as Oracle, MS SQL, or DB2. Of course, the answer is that Postgres doesn't have all their features, and never will, but it is also true that those other databases will never have all of Postgres's features. The better question is whether Postgres has all the features you need for a successful deployment, and the answer to that is usually an enthusiastic "yes".
This gets into the larger question of when something is good enough. Good enough sounds negative, like you are giving up something to settle for a partial solution. However, good enough is often the best option, as the negative aspects of an ideal solution (cost, overhead, rigidity) often make good enough best. In response to Oracle's announcement of new hardware, this Slashdot comment captures how great good enough can be:
I used to work in exclusively Sun shops, and I've dealt with Oracle for years. There's little that the hardware and their database can do that can't be replicated by x64 and something like Postgres with some thought behind your architecture. For certain, the features they do have are not cost effective against the hundreds of thousands of dollars you pay for Oracle DB licensing, and the premium you pay for SPARC hardware and support.