Yep, the T4 is dino
T5 is synthetic blend (and NOT marked JASO MA so I don't use it in ATVs)
T6 is full synthetic.
I've started using the T6 in everything except new motors during break-in. Smoother shifts on my footshifts and the wife's Rancher AT, and the liquid cooled bikes seem to run a little cooler with the T6
For $14-15/gal it's a no brainer.