I love my 550. Though I guess it will be replaced.
Don't let the price throw you, you get more than what you pay for. It comes with the RAM mounting for the bike, plus an extra cradle and mount for the car. The car mount cradle has a built in speaker and microphone, so when the unit bluetooth coneects to your cell phone, you have the best hands free set up I ever had for my car. It even down loads the numbers from your phone, so you use the GPS to select the number and dial.
If you bought a less expensive unit, and then all of the hardware you get with the 550, you would end up paying more than the 550 package.
Cheers, Len S