I run the lid with my 1800. I like the lid and wouldnt use the pack without it. It stays securely without flopping around. I always put the center pack compression straps across the lid straps which help hold it secure. And now that someone mentioned it I think I had to buy extra straps to work with the 1800.
I just ordered an 1800 with a lid. Should be here this weekend. Being in New York. I don't need a large pack. 99% is the day hunting. I want to be able to use it for hiking with the family as well. Hopefully next year I can get away for a long weekend or more. In that case I would order the 4800 to go with this