I have a Zumo 550 and it's been a real work horse of a unit. Has all the features I want and need and so far I have had very few issues. However was thinking of upgrading to something newer. I don't use a Bluetooth headset and don't want to, so using the headphone jack/ audio line-out works just fine for me. Was looking at the Zumo 590LM, so if you have one could you give me a review. Can't afford the latest and greatest Zumo 595LM and the Zumo 396LMT-S does not have the headphone jack/ audio line-out I want and need. Thanks folks.