This is only my third year "in the woods" coming there from a roadie's experience . Just some more info which may influence my choices, I'm 67 and not racing, really not group riding either. Picking my way through intermediate level trails with little drama, much like "trials" motorcycling. Speed has no influence on me, except for the occasional deliberate, adrenaline boosting run for fun. I'll pull over and let the quick ones by...just gives me a chance for a drink and a blow.
The first two years out there made me question my rigid choices, but this year the sun poked through my noobish cloud cover and suddenly all's right with the world again! I'm not feeling beat to hell after a ride, seem to have more than adequate control of the bike's and my balance, and sure haven't spent much time rebuilding suspension components. Experience is a GREAT teacher!
I have one bike that's undersized deliberately, then modified to fit comfortably. It's extremely handy...easy to lift the front, back or both on demand. That bike is a mid '80's Fuji with the original rigid fork. My other bike is a 2011 Trek that has it's coil fork replaced with a rigid Soma. I thought the whole idea of "suspension corrected" rigid forks were to keep the original geometry close to what the designer intended? No matter, for me anyway, as it handles very well and does what I need.
I can sure understand full suspension if you're "at speed" for most of your ride, that choice is obvious. If you're in my situation, rigid works, and works well. I'm in the woods and travelling much faster than if on foot. Matter of fact, I'd fall more hiking the trails I ride than I do riding them!