I don't think I've ever been a fan of big ol' squishy beds that you sink way into. Eight and a half years of sleeping on a dense futon mattress served only to reinforce this preference by dint of habit. The relatively firm foam mattress that I got, which felt okay during the brief lie-down at Ikea, did in fact stand up (so to speak) to a full-night's sleep.
And the other thing that I do genuinely like about sleeping close to the ground --- though I am giving up on it in no small part for the sake of keeping up appearances :P --- is that you've got a guarantee that tossing and turning around doesn't make a huge racket of bed-frame (or for that matter, mattress-spring) squeaks. Once upon a time at 5330 Beeler (which puts the date at somewhere around 2003 most likely) I bought a used futon frame off of misc.market just to put the existing mattress on. I put it together and it complained squeakily every time I made the slightest movement. I had night full of dreams of falling, mechanical failures, and injury, and put the damn mattress back on the floor the next night and considered it a noble failed experiment.
Anyway, this bed is good. I like it. It might have been nice in some ways to have gotten a larger one, but the bedroom wouldn't really take a queen very comfortably. I know I'm not in as much pressure to be frugal as I was during grad student days, but it is also a nice feature that it was pretty dang cheap, as beds go. FJELLSE $30 frame + SULTAN FLORVÅG $99 mattress + SULTAN LURÖY $30 set of curved slats.