Give me the name of the book included in the UM Omnibus please.
If i'm correct, it's the 3 first book.
(So they are decent correct)
The first, has some errors, but i enjoyed the story.
The second had enormous errors, but the story was made in an "epic" way.
The third, is decent. Interesting point of view, of a chaotic world.
The next (4-5-6) are pure bullshit sadly
I think the 4-5-6 are not included in the Omnibus.
But single romans are better when you start discovering the warhammer 40k universe.
Because you will learn much more about different chapter / factions, etc...
Reading a trilogy of the same hero wont make you learn much.
By the way, the small book " For The Emperor" is pretty cool, with some humour (which is rare in war40K) and a very good story.
It's one of my favorite, but i don't advise to read it as a beginner.
@joseph porta : Go read the Horus heresy books, if you didn't yet.