I'd think grafting might give a slightly higher percentage of success (although, as you said, Metasequoia is very easy to grow from cuttings), and, might require less initial care (young cutting-grown Metasequoias have a fragile root system).

I think you could get a lot more first-hand knowledge about this in the Conifer Forum.

I am growing mine from seed.

"I am growing mine from seed."

Metasequoia cultivars cannot be grown from seed (except possibly the original plant to start with).