So; we have the second week of results.
To set the stage: ISP caches will be cleared, so we might see desktop drop. Weekend traffic will show up, which means we might see the type of people accessing wikipedia change, and bring new preferences and demographics into play. It's been longer since the switchover, so people who dislike the change have had more chances to find the opt-out. It's the data wheel of fortune, and nobody knows where your spin will take you!
The answer is "a good place". The weekend made absolutely no difference; it bumped the amount of desktop traffic by a tiny amount, compared to a big increase for mobile, which suggests not just that most people have happily switched over but that the people who have switched are our most frequent and active visitors. Day-on-day, we saw no significant increase in desktop opt-ins - in fact, a slight decrease from the (already tiny) 5-ish percent.
Looks like being WP:BOLD and switching our tablet users to mobile in one fell swoop was a good decision, and our readers think so too :).
