Hi! Yes I prefer EM and crit generally, because with that my Kazuha can still give a 20% (30% if his ult is up) elemental bonus while still doing good numbers himself. The last screenshot is a 4 VV with anemo, attack and crit, which is not something I use regularly because it uses pieces from Xiao and Venti and I loose the elemental damage bonus.

As for if Kazuha is better than Xiao, I'd say generally no. My Kazuha is better than my Xiao, but my Xiao is only C0 with medium investment, while my Kazuha is C6 with high investment. A high investment C6 Xiao would easily out-damage my Kazuha, since Xiao is specifically designed to be a DPS while Kazuha isn't.