HMG Junction 3400 here. 55L has served me well for trips up to 10 days so far. Will be interesting to see how it goes with an 11 day packraft mission coming up later in the year, but over the past nearly five years it's proved to be a very comfortable, flexible and mostly very tough rucksack. My own real criticism is that the Hardline 150 material for the hip and side pockets isn't as durable as the rest of the pack and I've had to patch/glue mine multiple times since. Tassie scrub takes its toll. In hindsight perhaps the Northrim is the better option to get.
That said, as HMG won't do a Porter 5400 with Northrim hip pockets, my next pack will be a custom made Southern Lites alpine pack of 85L (for packrafting and ski touring).
Previously I had a Arcteryx Bora AR63 which was a lovely pack and very comfortable, but weighed quite a lot in of itself and just not as flexible with actual packing. Once you've had a roll top, you can't go back, basically