Question for those with extensive experience with both epics and omnibus

Which series collect more/less/the same as their omnibus counterparts? Or even other HCs, it seems like many HCs are missing tie ins/accent books when it comes to Marvel.

I'm open to any you know about but its generally for big names (ASM, Wolverine, X-Men, Mutant spin offs of X-Men, Venom, Avengers, etc)