Snowflex is quick, quicker when wet.
Thing about dryslope is that it's extremely consistent. I ski dryslope most weeks and I always know how fast to hit stuff (rails/kickers). The only time I need to "learn" how fast to go for stuff is when I visit a different place.
It's great fun skiing on dryslope, but as most people will agree it doesn't always substitute well for snow.