While saving up for a new generation GPS I am looking at installing an early model GPS unit. Trying to make a decision between the GX-50 and the slightly newer GPS-150 series. I understand that the GX-50 was an Apollo designed unit but I don't really understand if the Garmin GPS-150 (or 150xl) is fundamentally better or worse in terms of performance and reliability. Both units can be had on the used market for about the same cost. Of course King is another option. Any feedback on the pros and cons of each unit is appreciated!