Stephen Planck offers some advice:
Database snapshots are one of those features that’s been around forever, but still solves real-world problems with very little setup. In a single statement you can capture a point-in-time, read-only copy of any user database, use it for reporting or off-load testing, and—if disaster strikes—revert the source back to that snapshot in minutes. This guide explains how snapshots work under the hood, walks through day-to-day tasks (including creating the original database), and highlights the pitfalls you should plan for before using them in production.
One additional tip that I’d offer: limit yourself to one database snapshot per database. There’s a performance cliff you can hit when you get fancy and try to have multiple database snapshots going at the same time off of the same database.