Top-quality wifi speakers strike me as pretty much the toys you give someone who has everything. I knew an engineer who would install a proper audio system for CHF10,000 with hidden wires throughout the house (speakers extra). Unless you can afford that, don't even bother, is my view.
For those who need an alternative, the French magazine Que Choisir tested some ten boxes and blessed the Sony SRS-X99 costing CHF460. Its second choice, the Cabasse Stream 2 costs CHF399. But can give you stereo if you buy a second one. It uses up its power faster, though.
I'll stick with my CHF1000 wired speakers and surround-sound unit, thank you, and my CHF100 wifi box for the rest of the house.