I've been looking at the Speedy Yote for a year, decided to buy it when I saw the sale, and my short experience has been positive. I have 8 sets in 2 days on it, about 8 hours of hunting/walking.
I'm a pretty big guy, 6'4" 320 lbs, 42" waist 56" chest. It's been cold the two days I hunted with it (0 deg first day, 10 deg last night), so I wore 2 merino base layers, a Mountain Hardwear Tech Jacket soft shell and a Natural Gear fleece jacket. I have the straps adjusted all the way out, but have no problem snapping them or sitting comfortably with them snapped. I sling my rifle cross body (carbine carry, VCAS padded sling) and walk in slung in front of my body, out on my back. It was more comfortable walking out with my rifle on my back than it normally is. No clanking/creaking, the hard back sheet spread the rifle out and there was no pressure at all. I carried a big heavy suppressed JP 308 AR (15 lbs + loaded... ugh) the first day because there's a chance of a long shot. Walking in was the same as normal, the pockets are at the side of my body because I'm such a generously sized human and didn't interfere with my slung rifle. Those of you that carry with a standard over the shoulder hunting sling might run into problems with your rifle rubbing or clanking against the metal frame/legs.
As far as function goes, it's quite comfortable. I accidentally took a short nap on it last night during the 4th set, somewhere around 2 am. Decided at that point to call it quits for the night, then flushed a big cock pheasant on the walk out and dumped enough adrenaline that I didn't get to sleep until 3:30 anyway. Oh well, who needs sleep?
I bought it because it looked more comfortable than leaning against a fence post or tree, didn't plan on making a bunch of use of the pockets. I have 4 mouth calls, 3 aa batteries for the remote, Shockwave remote, extra 10 rd mag for the AR, 5 extra 12ga rounds and chemical handwarmers in the pockets. I use a Shockwave with Foxjack, no chance in Hades that it would fit in any of the pockets. Will carry water bottle in the summer, but it would freeze in the winter so I stick with the beverage I leave in the truck for now.