I run oracle locally, but it's more just to keep my hand in PL/SQL and test out some features. I work with corporates who use it though, so need to keep up to speed.
IMHO, some versions of it haven't had good performance with smaller data bases - other versions optimized well for small db's. Seems to vary from release to release. I have used it for large web db's and have been pleased with the performance and some of the oo features.
Michael's point about shared hosting is a good one though. There's a different set of issues around db's in a shared hosting environment than what are faced with dedicated servers. The body of knowledge that constitutes best practices for Oracle shared hosting isn't as widely known as that for other DB's.