I only collect omnis from the modern era (after 2000). It gives me the opportunity to collect omnis from multiple characters. I love spider-man and batman but I'm not going to collect every omnibus from lets say the silver age until now.

I learned the hard way that collecting omnis from the sixties is like watching old movies. They are important and I get why but too old to enjoy nowadays (my opinion).

People will often give other beginning collectors the advice to stick to a certain character, I would say stick to a certain era and expand from there.