LoneRider bags are considered semi-soft bags ... they have stiffening panels in all sides to keep them in shape when empty. See this video...
The drawback is that LR doesn't make a quick-disconnect system that works with RE racks, or their own racks for RE, so they are somewhat permanently attached.
MoskoMoto bags are soft, but have a quick-disconnect system that works with RE racks. I went with MoskoMoto for that reason alone.