My patience with $100 CDN moto GPS from China has run out ! A real GPS that is not running on a Microsoft Windows CE with updateable N. A. Maps is what I'm looking for. If someone is upgrading to the latest & greatest I'm interested in less capable but reliable unit.
Take a look at refurbished units. Big savings over new and I and others have had good results with them. Another option is auto or trucking units. I've been running a Garmin dezl 760 for about 5 years now w/o issues. Minor weatherizing with some high quality duct tape and the occasional baggie if it's an all day downpour. The dezl 770 is Sena BT compatible. (the 760 is not). There are 5" versions of these too.
Part of the problem is when Garmin discontinues a model many believe it's replacement is less capable so few want to get rid of their old ones for several years. Check out ebay and see how many you find. Also, check out the prices for accessories such as mounts. You will see them selling for over twice what they sold for when Garmin was selling them.
I second Eric's suggestion of checking out some of the dezl versions.