Loading your target incrementally offers a huge performance benefit over running full truncate/reloads, but there is a danger of missing inserts or updates in your source system. It can take hours or days to track down the source of these problems (if it can be done at all!) and problems are generally not found until [...]
This excellent piece in DMReview deliberates on some criteria for selecting (or justifying) an ETL tool. We are struggling with this right now. Our shop uses a combination of Informatica and SQL Server DTS for our ETL jobs. With Oracle Warehouse Builder 10gR2 and SQL Server Integration Services both released as viable alternatives, we need [...]