>does anybody really enjoy a stiff, snappy UI?

Yes many do. Especially the snappy part. I've removed a lot of eye candy animations coded by well meaning devs at the request of users who care about nothing more that speed.

Animations can be a nice first impression, but if you use the app daily e.g for work or data entry you know how to navigate and you want as close to instant response as possible.

Maybe a smart pattern is animate in the early days for new users then transition into a more jarring and snappier world as they become regulars.