I like a pack that is large enough to hold 7 to 10 days worth of gear and food yet will be capable of compressing down small enough to use as a day pack once I get where I'm going and is capable of hauling a 90-100 lb load in relative comfort (if that's such a thing)
I used a Stone Glacier Sky 6200 for the first time this year and was very impressed. Initially, I couldn't make up my mind between the Sky 5100 or the 6200 so I ordered both with the intent of keeping the one I liked and sending the other one back. I loaded both packs and realized that with my gear 7 days worth of food was about all I could fit in the 5100 so I kept the 6200 and sent the 5100 back.
I used the pack for a 7 day elk hunt in Colorado in September and gave the it a pretty good workout for it's first year. Here are a few pics.
The pack loaded with all my gear
In this pic I have 1/3 of a boned out 6x6 bull on the load shelf. Pack out was just over 5 miles. I didn't weigh it but probably somewhere around 90lbs
This is a pic of 1/3 of a boned out mature cow being loaded on the load shelf.
Same load with bag secured
With the load on my back. This pack out was just a little longer than the bull but a lighter load....maybe 75-80 lbs.
Note in the first pic of the 6x6 the meat was in an Alaskan Game bag (and black trash bag to catch blood) which did not hold any kind of shape and the meat ended up in a big blob. You can see the meat squeezing out between the compression straps. The cow was put in a TAG game bag designed for boned out meat and you can see it keeps the meat in a much more upright position and was much easier to load and secure. I also learned after packing out the bull I didn't like the way the top lid pulled out away from the bag so when packing out the cow I detached it and put it inside the main bag for organization which worked much better. I won't pretend the pack made either trip fun but it was as comfortable as can be expected for that kind of load and I was really impressed with how well it secured the load. I should also note that Stone Glaciers customer service was as impressive as their pack.