yzstan--I'll be nice, before this thread gets locked. Do a search. Those 2 oils only have the same manufacturer in common. One is a full synthetic built from olefin polymers while the other is castor oil based. There's benefits and risks of BOTH, and you have to choose what's best for your application...which includes motor, riding style, premix %, plug type, etc...
Your best bet would be to look up the multitude of posts on this, read for about 2 or 3 hours, and you'll have your answer.