Which Airplay speakers are reliable?

I have two Bose SoundLink Air speakers. Often AirPlay can connect, sometimes not. And when not, it's the same for iTunes and for iOS: a long wait and then nothing.

I also have a Denon AVR-X4000. Same story. Chance of successful connection is about 4 in 5.

The only thing to get AirPlay going again is to power cycle all devices - which is a pain because it involves removing and replacing the batteries from the SoundLinks. I really would like to just play music without needing to fiddle with the system.

Questions:

• Are some AirPlay speakers more reliable than others? If so, which speakers might work better?
• Could it be that the problem is not with the devices, but with my configuration? How to fix? (Time Capsule with WPA2 Personal security. Already tried fixed IP addresses)
• Once AirPlay fails to connect to a device, is there anything I can do to get things going again that is quicker than a full power cycle of every device?
• I'm considering switching to Sonos - can anyone tell me if Sonos plays 100% of the time?

-Ron.