Finally finished this monster after struggling to get through it for nearly two years. It is the most challenging book I've ever read. I went though it with a plot guide and character map and still got lost all the time.
That all being said, I think its the best work of fiction I've ever read by an American author. It is stunningly brilliant. Time and time again I was left in utter awe of Pynchon's writing ability. IMO he is without equal in his mastery of prose, humor, depravity, and esoteric postmodern deep-dives.
It is a slog to get through but it rewards those who invest the time and mental energy and accept the challenge.