I liked them. They are long (around 4000 pages all 6 books combined) there are a lot of story lines going on simultaneously around the primary theme and there are a lot of characters to keep up with. If you are someone who reads voraciously and not occasionally, you might find them most enjoyable (assuming you are a sci-fi fan). The story has so many different story lines that if you read once a week or so for only an hour, you'll forget too much in between as one story line is focused on for 50 pages, another for 100 pages and so on. It can be quite awhile before the first storyline picks up again. I'm explaining this badly as I usually do. )Don't let me discourage you! I really liked them)
I know I found it quite entertaining and would even consider reading them again as it's been almost 10 years.