It kind of pains me to say this, but I'll say Sonos from about 5-6 years ago. When I first got a couple speakers, I touted it as the best consumer electronics experience I'd ever had to except maybe some Apple products.

Unfortunately, it has been consistently downhill the past couple of years. What used to "just work" now constantly has issues and glitches, and speakers I got just a few years ago that work great are now essentially EOLed in their software. I've definitely purchased my last Sonos product.