I still like the SS pose better. I like the XM pose but it feels like I've seen it a lot before. I like SS's "just shot the arrow" pose, it's not something seen nearly as much.
I also like the SS face better. The XM face looks weird.
But...
If the production can match the proto, XM wins in paint application. It's still too dark, while SS's is too bright, a happy middle ground would be better.
And in details, XM wins already. Although SS's flatter, compact quiver is more logical for an action superhero, the bulkier XM quiver still looks more impressive. The modern bow also looks better... SS missed out on an easy Ex by not having an alternate bow. What really helps the XM is the sculpted clothing details: wrinkles and stitching, arm bands and gloves.
The only detail I don't like on the XM is the "ears" part of the mask is too thick.
Overall I'm glad to see more great looking 1/4s. What we should really hope for is XM to eventually get official distribution to the US.