I have used a load shelf on and off. They're great when you feel like you have time or just want to save your gear from blood. However, it is just as easy to get a bigger bag and have a contractor bag or a dry bag for meat or gear.
My previous self was worried about getting the bag dirty because the bags were not easily cleaned. With the new material though, I would not be nearly as concerned with getting the bag dirty. The only other con to integrated I could think of is hauling elk quarters that you haven't cut hooves off of. On the breakaway, you can easily stuff those in the load shelf and have no issues, but with the integrated, I am imagining that getting a seal to where your gear wouldn't get wet in a rain storm or get a bunch of debris in there is difficult.
I guess there would be another con that I thought of during the order process. How hot can your meat get in that black material especially if you're putting it in a trashbag or dry bag to keep things clean. I could imagine it causing an issue on an antelope hunt.
That being said, I ordered an integrated frame. It is just simpler and easier to use in my opinion. And the best part is, if I don't like it and find the load shelf worth it, I can order a custom bag only and get exactly what I want and just add the revolution panel. This is coming from someone who previously would not buy an integrated pack because I felt load shelves were easier. After my deer hunt this year, where we hauled out two bucks differently, one in the load shelf and one in the main bag, I thought that it was 1000x easier to just stuff meat in the main bag. That is in a pack without an internal load shelf as well. I think that the fact you can have the same frame and do internal or breakaway is a game changer that made me gravitate towards Seek. I can just change in the future if I think breakaway is better.