The “X factor” regarding SQL Server backup compression in the next 24 months is SQL Server 2008. Backup compression will be built into SQL Server 2008 Enterprise Edition, and I suspect that many customers currently using either SQL Server 2000 Enterprise Edition or SQL Server 2005 Enterprise Edition who are upgrading to SQL Server 2008 Enterprise Edition will reconsider their need for tools such as those in this review because the backup compression built in to the new edition of SQL Server Enterprise Edition might be good enough.
You’ll be able to restore the compressed backups you make with SQL Server 2008 Enterprise Edition on other editions of SQL Server 2008, even though those editions don’t feature the ability to back up databases with compression. That makes SQL Server 2008 Enterprise Edition’s compression format portable. Anyone implementing editions of SQL Server 2008 other than Enterprise Edition will need a third-party compression tool.