I learned my hs backroll first, took me a day or two, then my tantrum took me just as long. I just landed a hs frontflip on my second attempt yesterday. I had them consistant, and I still don't have my backroll and tantrum landing consistant.
I've always been able to do front flips better than backflips on a trampoline, or in a pool or something. Maybe that's why I find it easier to do that, or maybe learning a backroll helped me in some way with the frontflip. Personally I feel more comfortable with the hs frontflip.
Tantrums are easy though because you have such a long time to spot your landing. Try them all a time or two, see which you're most comfortable with.