Clustering can be a very nice convenience, however, there is still the cost of ownership for the hardware to properly backup that type of HA solution. I'm not 100% sold on the TCO for the particular environment that our team supports. We do use mirroring though and that for us has a much lower TCO for how our environment is built. I have worked with a clustered environment before though and I can attest to the benefits. I also think your article does make a very good case for using it. I think it would be good to do a follow up post where you delve into the infrastructure requirements that clustering requires for the databases to perform well. Maybe a best practices type of posting to get people started on clustering if they want to go that route based on your own experiences with clustering and not just from various BOL articles and white papers.