As previously noted, it will feature on-board maps, voice and on-screen directions, a 3-megapixel autofocus camera, and one feature I'm very interested in: Garmin Voice Studio. This application lets customers record and share custom voice directions from family and friends, and while I'm still deciding if it's a useful feature, it's at least innovative.
The price point is decent considering that you get a built-in GPS navigator, real-time traffic, weather, gas prices, and still all of the Android trimmings. However, there's a lot of competition coming from other carriers, not to mention that most smarphones now offering free turn-by-turn directions, with Microsoft's Bing App for Windows Phone being the latest to join in the fun.
If the Garminfone had come out last year, I'd be a lot more excited. As it stands, it's an interesting concept but I fear it may be a bit late to the market.