Depending on if you want a synthetic or not.. At $130/ 5 gal I would guess its synthetic. The WM/TSC will probably not be synthetic.. You can get Amsoil synthetic (assuming it will be the correct specs) for about the same as the Kubota fluid..
BTW - If you fill our your profile completey we can get a better idea if you would benefit from a synthetic.
Kubota UDT is fine, you don't need super in that model. New Holland 134A is pretty economical and made for agricultural equipment. Buying the cheapest of cheap fluids is typicaly not a good idea. We've had customers tractor who've trashed their transmissions by running some odd ball fluids. Its not worth the $20 savings.
I just noticed the other day in the WalMart 5 gallon buckets of hydraulic fluid. I looked on the back and it listed Kubota UDT as a comparable. If I recall correctly, the price for the 5 gallon bucket was $59!!
I would have bought one but I didn't feel like carrying it that day.
Regards, Glenn