User blog comment:Crimson Storm Mich/Guide: Omni Evolutions and the SP system/@comment-27771011-20160408200749/@comment-28108550-20160410161124

The thing is it is what you want to do. Just like when 7 stars first came out the heros seemed MORE overpowered than the rest since there is the evo gap. You should still summon for units (like for Global the GE's). But due note the cost for omni is 3mill zel and 1 mill karma, 2 mech totems and a legend stone. Sure if your new and you can scrape the cost (by getting a friend that can solo the mecha or such) but there is still the leveling. The levels are progessive meaning lv2 will cost MORE than 1 and so on. But due to this lvling up from 100 to 120 is alot ( i think like 4 or so crystals) but from there 120-150 is ALOT. But if you are not planning to currently max, YES mostly selena since her OMNI's heal can make the earlier trials and the 6 hero's pretty easy.

Solid investment, should still try and summon