Thanks for the comments guys!
muleman
There are a few thing I did not like about using the bag in the load sling mode, and loss of load lifters being the main one. I am not a fan of how the bag rides with a load of meat and a full bag that is sticking way out there. Yes you can cinch it down pretty tight but to me it made me feel off balance.
I also did not like that there was no way to elevate the meat on the load shelf to the middle of the frame like I normally have if the meat is in the bag. This caused the load to have a sagging feeling and had me hunching over to compensate.
The extra time it took to change over the bag is another. It is so much easier to just drop the meat in the bag and go. Using the load shelf I found myself messing around for a long time trying to get everything right. I'm sure a guy would get faster at doing it over time but I really don't feel its worth it.
When I bought the Metcalf it was for its size, sleek design and frame extension. I never really cared about using the load shelf, so I don't really see it as a down side of the bag, and just as a feature I'm not going to use.