I heard Darrellw4 on the Podcacher podcast today and he had been to a Garmin/Groundspeak event and they demonstrated the improvements to the Colorado. There have been some software updates most of his complaints have been addressed and now the device is just about ready for prime-time.
So if you get one soon, be sure and download all of the updates. Not to mention you can do the WhereIgo caches with it.
Sounds like Garmin really listened to the consumer.