Re zero is better. Sao is not worth watching in my opinion but if you want to try it yourself go ahead. But i would say try re zero first

Re: zero has a more good story but it will bore u, but SAO is real entertaining, bother are in my top five but I like SAO a little more so I've to say watch BOTH but SAO 1st

If you like interesting characters, good plot, a trap, compelling motives, consistent storytelling, great character design, go for Re:Zero

I think SAO is worth watching it has a good story, Re:Zero is good too but not as good as SAO, Subaru is the worst anime protagonist I’ve seen so far, I just think he’s a bit lame.

Subaru is meant to be like that. He’s meant to be what a normal guy would be like in a messed up situation.

I think Re:Zero is far better. The characters, and plot are good, and Subaru is way better than Kirito.

Re: Zero don’t ever watch SAO