I can't comment too much about the HMG other than pure observation, however, I have had a lot of friends who own CiloGear and I have used CiloGear packs personally. In short, no sir, don't like them.
Lately, I have been ruminating a lot on what makes a pack good. My nearly 12 year old Serratus Genie, after many seasons of hard use, is finally starting to become thread bare. I've bought three different packs to replace it, returning each one because of their short comings. So, what makes the Genie so great? Simplicity.
I call it the Space Shuttle syndrome. After the space shuttle exploded it was determined that a small O ring failed. The engineers knew there was a chance the O ring would fail, but the chance was acceptably small. What they failed to consider was there were many, many O rings on the rig, each with a small chance of failure. When statisticians went back and crunched the numbers, it turns out there was a 50/50 chance of catastrophic failure due to the O ring failure alone.
Packs rarely fail by the fabric tearing. Expensive Full Dyneema/Spectra (woven or non-woven) are effectively no more durable than spectra grid rip stop. Maybe a bit lighter. Packs fail when seams, stitching, and zippers break. CiloGear packs have more seams, patches of different fabric, straps and do-dads that all have a chance of failure, and fail they do. Removable straps equals losable straps. Very little point in stripping a pack down for a summit push. How much weight is actually saved? A pound?
A few years ago, a friend and I were returning from a winter attempt on Ptarmigan Ridge on Mount Rainer. The climb involved skiing the closed HWY 410 and White River Road (24 miles round trip just to get to the summer trail head). After several days slogging on skis in heavy snow, we called it and turned tail. When we reached HWY 410, we discovered it had just been plowed. We put our skis on our packs and started walking. I could literally hear the straps snapping off of my partner's CiloGear. It was his third one in three years, they all fell apart. And he was just a weekend climber.
So, I like simple, but I also like functionality. I need a pack to carry ice tools, crampons, pickets, tent poles, sleeping pad, rope, and skis on the outside. Not all at once, but at one time or another. I want no unnecessary zippers and no extra pockets. A pack should have one large main compartment, large enough to carry my sleeping bag, tent, stove, rack, clothes, food, rock shoes, and other necessary crap. I like a top lid pocket to hold small items I need throughout the day. I have used some roll top packs without a top lid, instead have a small, externally accessed pocket. Not my cup of tea, but acceptable, and simple.
The suspension should be adequate for the job. Packs small enough (30 liters) need only a foam back pad, lightly padded shoulder straps, and a 1 1/2 " waist belt. Larger packs benefit from some type of rigid support for loads greater than 35 pounds as well as a padded waist belt.
Take a look at the Cold Cold World Chernobyl:
http://www.coldcoldworldpacks.com/chernobyl.htm. Randy is very amenable to custom work. You could have the whole thing built with Dyneema grid fabric, nix the daisy chains and ski slots and have a extremely functional and durable pack that weighs not much more than the HMG or CiloGear.