We have a bunch of them, and for the most part I absolutely love them. The only big downside is the desktop version of the app is a real hassle and often locks up. The iphone app is much better and smoother (especially reliable when playing something stored on your phone or using a streaming service), haven't tried it on an android. That said, there is a workaround that allows you to play it via apple's AirPlay, which is easy.
It does really change the way we listen to music at home though, and definitely for the better. The easy grouping/ungrouping of different rooms in the house is really convenient for both playing one thing in every room simultaneously during a party and then later listening to something by myself in our bedroom while my wife listens to something else on the porch. When it works, it actually does that weird tech company thing where it really solves a problem I didn't know I had.
Full disclosure, we did an ad for them a while back, which was how I ended up trying their stuff out in the first place.