Just gave a driftglobe to the players and was reading the details to help explain what it does, but it seemed mostly useless, except for the once a day daylight spell. It reads to me that it follows you 60 feet behind, but a light spell only has a 20 foot radius of bright light and 20 more feet of dim light. So if you were in a totally dark environment, you would still be in darkness with no way to see where you were going. You would get a great view of where you had been though, as well as alerting anyone ahead of you that something was coming. I looked around for any errata, but didn't see any. It seems less than useful, if I am reading it correctly.