Trades win easily when it comes to reading new material sooner.
Most every regular series from Marvel and D C will get a trade (some time a small hard cover) and than another and maybe another
before a hard cover is collected, With Omnibuses the gap is even greater.
So if a person wants to follow on going series, but does not wish to get single issues, than trades probably will be a better fit.
They could wait a year plus and get a deluxe hard cover book, but that would put them over a year behind on new material
and many series never even make it to hard cover (I keep holding off getting All New Wolverine vol.2 because I would love to have this in omnibus).
At the end of the day it all comes down to personal preference and how far a person will bend.
I switched to trades and hard covers only less than two years ago. So I missed out on many omnibuses
I now wish to have but will not pay the high prices to get. I will wait for Marvel to re-issue some, but
others I don't want to wait for and so am getting trades as they get released like Jonathan Hickman's
Fantastic Four.
Epics are nice, I have a few and will be getting a few more. I read a lot of Marvel between 1972 and 1990
Epics give me a chance to read a lot of those old series like Defenders and Incredible Hulk and Champions,
while still focusing on series I want in Omnibus like Bronze Age Amazing Spider-Man and Avengers.