I replaced my 750 and 650 with Xi units. They are great. They boot nearly instantly, the screen is nicer, and the touch interface (smoothness in panning/zoom/etc) is much better. However, right now there is no strong compelling reason to upgrade, as there is no functionality differential (other than speed and pixels) vs the older units, but I'm sure something will come down the pipe soon that will be Xi only. I did the upgrade now, because I felt that I would eventually want to do the upgrade and the cost to do it now is likely the lowest it'll be (resale on the original GTNs will go down over time and cost of Xi will go up overtime as Garmin products do).