I have had a number of GPS units for my bikes, and now have a Garmin Montana 650T - tops in my book. I can use it for a number of applications, run it for 16 hrs on the battery, then pop out the Li battery and replace it with 3 AA batteries for another 22hrs... It has BOTH streets and Topo maps for all of North America, and readily switches between them. It also has an 8MP camera, and if you take a picture of a landmark, will route you to it...
I started with a Leader mount, which was very well made, but offered limited security for a $500+ GPS. So I hit Ebay, and found the wired Garmin lockable mount, and a multi mount for the RT, to replace the Leader unit. I stripped off the right side tupperware, and found the BRP harness, and hardwired the switched power to the mount. Could have added voice to my radio, but I didn't/don't want it - it's iTunes/iPod or wind on my RT.
The mount was easy to install, wiring, not so much, but doable in an afternoon. All in all, I'm pleased with the results, and it's almost identical to what I had on my 2010 RT. Plus, it's as secure as you can make it - so I don't have to remove it, if I stop for a meal, or walk down a trail....