There have been more and more units coming out with lifetime map updates. I would expect a $700 device to include those lifetime updates. Too bad it doesn't. The Montana does have a motorcycle profile which is interesting. It also supports the heart rate monitor and bike cadence sensor along with CHIRP for us geocachers.
GPS City has a bunch of videos going through various modes on the 600.
After watching the videos I'm probably going to do a pre-order. Unless Garmin really screws the pooch on this it should be a really great unit. Boo on the lack of lifetime maps.