No, not everyone is using Yabukita clones. There are some regional preferences for varietal, like Sae Midori in the south (Kagoshima) moreso than Yabukita in Uji or a mix of varietals in Shizuoka - a lot of blending happening. Uji labeled tea has to be over 50% Uji, but they also produce a lot of blended teas in the old Kyoto shops.
Kagoshima, full body, brothy but tropical fruits. Warmer growing area makes an earlier harvest season.
Uji, traditional methods, nice long leaves, perfect balance of umami, astringency, bitter, hint of sweet.
Shizuoka, medium body, sweeter.
These can certainly vary. Most of the fun is in drinking yourself, so, drink up.