Hard to say. I do like the classic elegance of the Tokyo version. Hong Kong doesn't do it for me. Walt Disney World has a pretty cool one, sure. Ours is...fun-looking, but entirely inappropriate to the intended theme of the land. So the prize has to go to its twin, the Astro Orbitor in DLP's Discoveryland. It looks cool like ours, but it actually fits the theme! What a concept!
My vote is WDW's redone 1994 version. Most "futuristic" design of them all.
TDL's ... is unchanged .. since the park opened - 1983, and is a copy of WDW's 1972 original. Old and out of date.
DL's Astro Orbitor which is a perfect xerox copy of DLP's Orbitron is a dressed up design of DL's 1967 Rocket Jets - jets. More about the "retro" Jules Verne look. Nice colors .. but not truly futuristic from our perspective.
Sorry, forgot that the DLP version was called the Orbitron. And it's certainly not futuristic...it's not supposed to be. "The future that never was." That makes it perfect for DLP, and dreadful for Disneyland.