Pot Odds vs. BE %

Just starting to really apply math to poker to improve my game.

I myself find it easier to come up with Break Even percentages for my hand and outs versus the percentage I am investing in the flop.

I use the rule of 2 and 4 to find my chance of hitting an out and basically go from there.

Is there any advantage to using either one? What do you guys use when calculating odds and why?

I was also wondering if a rule like 2 and 4 could be applied to Omaha even though the number of hold cards are doubled.

Thanks for any insight.