I have no experience with the Garmin but I recently bought/installed A70D. When I bought it they offered a $500 mail in rebate, not sure if they are still doing that... For the price (with rebate), nice machine. Kinda old school sturdy, push button (not touch screen) design that I wanted. Not super user friendly but after reading the manual a few times, I've figured it out. The factory screen presentation options were dumb (no compass, no speed, etc). But you can manually configure the screens to your preference (must read how to do this). The depth finder works well until I get into really shallow water then blanks out (2-3'). The transducer may need some adjustment to fix this.
Installation was fairly straight forward. I had to cut the power coord b/c the hole in my transom was too small for the big receptacle to fit through. If you need to do this, order the junction box to splice the wires. With the junction box, it was easy and worked right away.
The screen is a little dim for my liking. This could be due to the setup on my dual console. I do not have enough room between A70D and windshield to tilt it around. I heard the dim screen is a common theme for many color displays of all makes/models.
All in all, can't beat it for the price. Solid unit.
