I think DB2 was the first DB I used with perl. DBI, perl and DB2 so far has been my favorite. I have found that DB2 was much more "forgiving" in terms of dealing with a slow programmer then anything else I have encountered since then.
I used it on a OS/400 system. The queries I was doing were intense. The data was spread between 2 tables and millions (literally) of records. I used quite a few multi tier queries (a query which subqueries, which subqueries, etc.) and it handled it like a champ. My only problem being determining the difference between DB performance and what was just raw hardware horsepower from the AS/400 I was using.
either way...perl, DBI, and DB2 was a pleasure to work with.