The first was a very soft, pillow top innerspring mattress (toddlers weight) and had no real edge support. As daughter recently got her own room we have to calm her sleep (sometimes several times a night), which means often falling asleep on the edge of the twin bed. Which means without edge support barely being able to walk the next day. This choice was our mistake for not thinking it through. Exchanged for same brand memory foam. Twin seemed great on the showroom floor, but we elected to move to a full (dual use when visitors visit and move us away from edge) and I suspect because of construction, though we may have had a lemon that didn't cure correctly*, now the 25% outside edges are as/nearly as firm as the showrooms (which is a year old and should have more give than our new one), but the middle 50% isn't. Went back to test display and confirmed. Now it's miles better than the first bed, but already feels like it's 5-10 years old and sagging in the middle (though I suspect it won't get much worse in near future being mem foam). Now we could probably live with it, but two weeks in don't want to (especially after Doug's story). Options in same quality/price point, are to go back to twin in memory foam (hopefully would be like showrooms) or firm version of first innerspring, likely in full, to keep away from edges. If next step up was a minor cash outpouring we'd probably do that, but it's unfortunately a doubling (as my options now are locked to dealer).
* Sleep like the Dead says "At least 12% of memory foam bed owners say the bed they received has significantly different firmness than the one they tried in a showroom."