In reply to wbo:
> - you need a harness that fits, then they're comfortable. I own a BD momentum, it doesn't fit, ergo it isn't comfortable. Amount of padding is barely relevant compared to the shape.
All of my harnesses fit me as they should. They are all comfortable to wear all day and sit in them. The problem arises on hanging belays where, because you're leaning back, you put all your weight on the back of your waist belt.
On the Syncro, for example, once you've used it for a couple of months and the padding starts to lose its firmness, you're only hanging on a thin piece of webbing protruding through the padding.
Of course that the amount of padding and how well the padding/webbing distributes the load are important in this case. If it wasn't, big wall harnesses wouldn't have so much padding. Exception are Arcteryx harnesses, which don't have a lot of padding, but the way they weave the webbing distributes the load evenly across the harness. Unfortunately, I have tried them in every size that I could actually get on (M through to XL) and on none of them could I get the gear loops to be centered.
I have had one harness which was very comfy on hanging belays, the Petzl Adjama, but again, I couldn't get the gear loops to be centered no matter which size I tried.
You can make the case for single buckle harnesses all you want - unless you happen to be smack in the middle of the size range (which I'm guessing is the case for you and Alan), you'll have issues with them either being too big and sliding off you or one of the gear loops being too far back.