I've had some MR packs. For what it's worth I've personally used the Marshall/FILBE/Beartooth packs and my opinion on them is that they suck. That being said, I have one of their 3 day assault packs and I absolutely love it. I use it all the time and it's one of my go to packs. The other ones are way over priced for what little you get. The fit/comfort of the pack is horrible, which for me is about 80% of why I choose a pack. I switched to a KUIU ultra 7000 a number of years ago and have never looked back. Yes there are some minor things I would like to change on my KUIU pack, but they are negligible. For me there is a night and day difference between the big packs.
I have the MR bear tooth. I like it. Can’t say anything negative about it. I’ve also had my eye on the KUIU packs. No particular reason other then it’s something new. I might be wrong but I thing the MR was one of the first packs to adjust to allow for a “shelf” for meat hauling. Seems to me Kuiu sort of copied that idea. I just can’t justify another $600-$700 for a new pack to replace one that works. Are they any good….???? I say absolutely. Are there better packs??? Maybe. I think you really need to try on packs to see if the fit and frame work for your individual body. I don’t really like Eberlestock packs. They just don’t fit my body but many many many people do like them. To each their own