I have used the Ortlieb Plus touring set before, and I love them. I feel that they are some of the best panniers on the planet, and I have used lots of them in the past 40 years and on 3 continents as well. I particularly like the extra size given that I often travel with light mountaineering gear as well as my biking stuff. I am in the planning stages of a North-to-South America trip where I will also be carrying a folding sea kayak with me on the bike, so space and efficient packing are even more important to me than normal. If all one is doing is a bike tour, I believe that these panniers could be too large—it is my observation that many bike tourists (except possible bike-packers) pack far too heavily beyond what they actually need. But for those crazies of us who love multi-sport bike touring (skiing, climbing, sea-kayaking, etc.) I love the large size!
I actually have not used these new ones that I bought for a bike I keep in California (I live in Alaska and have a set there). It came after I already left for a road trip, so the new ones will have to wait for a while!