I love the Silmarillion. It's the Old Testament Bible of an alternate universe. It's not a novel so much as a collection of mythological stories and a narrative history, very much in the style of medieval literature.
It is so much more epic. Did you find the Balrog in LotR impressive? Imagine a hundred balrogs riding on dragons storming the the elven city Gondolin. You find Sauron an impressive evildoer? He was only the Lieutenant to Morgoth. You can argue that this is just inconsistent unedited early material, but I don't care. ;)
The first time through, it's as has been said, the stories aren't very detailed, they're more like old testament books. You definitely have to use your imagination. Also, more and more of the lore is revealed here as well. And then there are the names. Oh, the names! So many to keep track of!
I think I really started to get the Silmarillion on maybe the third read. After that it gets easier and easier the more you retain of the stories. It is certainly my favorite Tolkien book after probably five reads or so and I find the stories to be really rich and interesting now.
You're right, though, Sauron? But a servant of Morgoth! The stories regarding the Silmarils are my favorite of all of Tolkien's stories, which, of course, span many stories. And don't forget Ungoliant for pure unbridled evil!
Uh, who is recommending these books to these people and why aren't they at least reading the descriptions?
(Or perhaps that was the intent. Sigh...)
10 years later I came back and read it again. This time I had read more mythology and understood the Silmarillion as a book of mythology. I very much enjoyed it the second time. I think age, experience, and expectations had a lot to do with how I viewed it that second time. It's a totally different book than the Hobbit or the Lord of the Rings trilogy. Anyone who isn't expecting that will end up disappointed.