Last Novembers SV Astro Camp, I was presented with an XW.
That night was spent on the observing field with the 'XW', and 'Nagler', and 'Takahashi ED' EP's in and out of the scopes regularly.
The outcome: No easily discernable difference!
Actually, the owner of the Nagler felt a bit ripped off coz his Nagler cost a lot more.
We observed a lot of different objects to do the comparison properly.
My own opinion: They were all great, and no favourite was chosen. They were all . . . ummmm . . . amazing!
But I still also use my GS EP's, and they keep me happy too.