Magellan eXplorist 510 Hiking GPS

Mixed decides on Amazon. Many of the negatives seem to be on the cost of additional maps and the need for an sd card.
https://www.amazon.com/gp/aw/d/B003Y5H17I/ref=mp_s_a_1_1?qid=1465731760&sr=8-1&pi=SY200_QL40&keywords=magellan+gps+510&dpPl=1&dpID=51EhYpUKljL&ref=plSrch