ive never tried backflips, but they seem easier than corks. THen again i have never tried corks....but still. Corks seem like there would be alot more worry about getting off axis, then back on, while backflip you just throw it and ur basically still on the....y axis? (math talk warning)
point is backflip seems easier. I backflip off everything else (stumps, buildings, tramps, platforms into water, etc...) im bound to try them first on skis.