which one is easier?

I've heard that a tantrum is easier but it's all personal preference.

I think that the backroll is easier. The tantrum gives you a ton of time to spot your landing, however, I find it hard to time the pop and turn the board to give the "tripping" motion. The backroll feels more natural to me.

I learned the tantrum first but i feel the backroll is easier. Play to your strengths, if you have a good progressive edge try the backroll. I think it's easier cuz you have both hands on the handle and the trick just completes itself.