Hi Paul,
We use SQL Sentry's Event Manager for all our managed customers and it works brilliantly. The guys at SQLSentry are a good bunch too which makes it easy to discuss any additional requirements or feature requests with them. I really would suggest you get a trial license from their website and give it a go before you write it off 🙂
Regards,
Christian Bolton
MCA: SQL Server 2005, MCM: SQL Server 2005/8, SQL Server MVP
Technical Director - Coeo Ltd