The memory foam will be heavier than an equal-sized coil spring. But the memory foam was more comfortable for us (YMMV). Be sure to get the memory foam that has the gel in it if you are going to be staying in hot climates -- the non-gel memory foam mattresses will sleep warmer at night. /ken
Ken & Deb (WIT Club, FMCA, SKP, Harvest Hosts, and grateful volunteers with SOWERs)
2005 Winnebago Vectra 40FD w/400ISL and Allison 3000MH on Freightliner's Evolution chassis, Onan QD7500, 1000w Renogy solar, BlueOx tow gear, and 2015 Cherokee TrailHawk toad.