I have found Postgresql useful for home (running a hobby site) and at work
(even though we have a site license for Oracle administering Postgres is
simpler and one of our DBAs is using it for a couple of projects including
one I am working on).
I find the documentation to be very accessible. Because it is concise and
readable I find myself just reading through parts of it to see what is
possible. Form doing this I learned about scalar subqueries which I think
can be very useful, but don't seem to get much publicity. I also have had
things carry over to Oracle (whose documentation isn't as practically
accessible). For example I tried using an insert coming from a select
in Oracle because I knew Postgres allowed that. I was having trouble with
the syntax (because I was combining a constant with results of a union
query and was having trouble properly naming things) and went looking (using
google) for Oracle documentation on insert (incorrectly thinking that maybe
this wasn't something Oracle allowed) and couldn't find anything that mentioned
this feature existed.
I am looking forward to 7.3 and have been looking at the development
documentation to see what new is going to be in it.
Thank you for making this great product available.