I have a Road Tech 660LM, Like it but am thinking of moving up to the 590 for the twisty roads feature and the larger screen. Bitch is I have to pull the fairing outet and tank again because the mounts are different. Also, the TPMS feature on the Garmin version is disabled on the road tech.And the $800 price tag.
here's a factory refurb for $499. comes with a 1 year warranty.