First of all, I appreciate all the helpful comments this post has received so far, but at this point I feel I need to clear a few things up:
1. "The pack is too small for you" theory
My torso size is 18", which is quite small for my height (5'10"). I am nearly always right on the verge between a small and a medium size in almost every pack I've ever tried on, and the same was true for the ULA packs. I either needed the small with the hipbelt adjusted as far down as possible, or the medium with the hipbelt moved vertically up a bit. I like to have the flexibility of a larger pack bag and I've also found that packs that are slightly too large are MUCH better than packs that are slightly too small (but YMMV), hence my choice of a medium pack.
I know I might have seemed slightly naive in my first post, but I was just trying to be humble. I know how to size a pack. I have sized packs for myself and for others for well over a decade. I am not getting my sizes wrong. Not sure what else to say about this.
2. The "You probably don't like the ULA packs because they don't have all the do-dads and extra junk found on most packs at REI" theory
I like a pack that is functional and well-designed. If there is something extra on a pack that is unnecessary then I generally prefer to take it off as long as that is possible without too much trouble. I am most certainly not attracted to packs that have a ton of extraneous feature that I don't want, don't need, and only add to the weight. In short, I think this line of reasoning does not apply to me, so you can rest assured that it is not coloring my opinion of the ULA packs.
With that said, I will gladly accept a weight penalty for a pack that has really nice suspension, but that's just me. If you want to nail me on anything, this is it. When a pack gets over 15 pound, then I immediately want 80% of the pack weight on my hips. That's just me, and I realize that I'm probably in the minority when it comes to this.
3. The "Packs stays should never, ever be shaped by the manufacturer because everyone's back is different" opinion
I see the reasoning in this argument, and I simply respectfully disagree. It is true that everyone's back is different, but they are not THAT different. Therefore, manufacturers, in my opinion, should go ahead and modestly shape suspension stays whenever possible to GENERALLY fit most backs, without doing anything too severe. This allows each user to tweak the stays if need be to suit his/her needs, but doesn't necessitate that they start from scratch. Look at all Osprey, Gregory, etc… ("big brand packs") and you will find that nearly all of their stays are pre-shaped. Some of you may hate this, and turn to ULA instead. I get it. But my argument is that for the vast majority of people (including myself), a moderate amount of pre-shaping goes a long way in making a pack much more comfortable right from the get go without a whole lot of fuss.
This is just a difference of viewpoints though, so to each his own. The point I was trying to make is that the fact that ULA does not pre-shape their suspension stays even the slightest bit is a big downside for me personally. YMMV.
4. "You can't get a very accurate assessment of a pack just by carrying it around the store for 2 hours"
Of course, this is correct. But I still stand by the idea that you can get a pretty good rough estimation of how a pack will or won't fit you, and my point was that I would most likely choose another pack over a ULA based on my in-store experience. I do not, and will never claim to be an expert on ULA packs without actually giving them a long-term try.
I simply wanted to relay my initial impression that I wasn't very impressed by the packs, simply because this kind of dialogue seemed to be almost completely absent from BPL until my thread post, and I wanted to get a healthy conversation going that wasn't just the same old party line of "ULA packs are the best thing since sliced bread" that we've all been hearing up until this point.
I have no doubt that ULA packs are quite excellent for some people… and for all the people that don't like them, they can take solace in this thread! :)