Thanks a lot Roger! I found your mini-reviews to be fair and informative. Worth waiting for :)
The comfort thing is the one issue that is, as you point out, impossible to get right. For instance, I found the GoLite Quest to be comfortable for weekend trips, but when loaded up for anything more, the pressure it put on my lumbar was unbearable. I find the Exos and Flash to both be comfortable with these heavier loads, and have no difficulty getting 10 days worth of (non-winter) gear and food into them. But I do make liberal use of all those frilly pockets to accomplish this ;) Couldn't agree more about those 'silly' whistles, but since I remove sternum straps anyway, they don't bother me.