Does Oracle support full text search?
Is there an Oracle equivalent to MS SQL's full text search service?
If so, has anyone implemented it and had good / bad experiences?
Oracle Text is the equivalent functionality.
I've had good experiences with it. Assuming that you are maintaining the text index asynchronously, that tends to be the first source of problems, since it may be a bit between a change being made and the index getting updated, but that's normally quite reasonable during normal operation.
In addition to what Justin said, you can find more information about Oracle Text here.
And further to what Justin said, it is possible to create the index so it updates on commit, although this is not recommended for large amounts of text.
It offers much more power than a simple LIKE compare against %string%.