I have and use an Eberlestock just one and it works fine. The construction is high quality (on par with my other backpacking packs). There are a few design issues I would like to see fixed, but nothing major. It does sway left to right when really loaded, but not too bad. Overall, I can comfortably carry a large amount of weight in relative comfort. I have it adjusted to fit my 6'4" frame quite well.
Most hunting packs have way, way too many pockets, straps, 1,000 molle attachments and features. They put them on there for marketing and they make the pack heavy and introduce more failure points (buckles, zippers, seams). In my view, the ideal hunting pack would be incredibly simple with few bells and whistles.
If I had to do it over again, I would seriously look at an external frame meat hauler.
With Kifaru, you are looking at a huge amount of money, at least double. They may be better, but at most I use it once a year. I think most guys would benefit more from training their body to haul the load than buying more gear. The few "professional" game haulers I have seen have beat up old packs that look like they belong at a garage sale.