While I find the app somewhat slower, that’s likely measured in milliseconds, not seconds, and I suspect, once that they’ve reached feature parity, the programmers will be able to go back to working, at least in part, on responsiveness. 

My guess is your 5 second lag has more to do with local network issues, with my bet on duplicate IP address concerns. Try unplugging all your Sonos devices from power, then reboot your router. Give the router a couple of minutes to reload, then plug back in your Sonos devices. Give them a couple of minutes to reconnect before testing. 

If this works, and I suspect it will, I’d recommend looking at your router’s manual and setting up reserved IP addresses for at least your Sonos, it’s not only good housekeeping, but will help avoid this issue in the future. 

However, if this process makes no difference in your situation, I’d suggest that you submit a system diagnostic within 10 minutes of experiencing this problem, and call Sonos Support to discuss it.

There may be information included in the diagnostic that will help Sonos pinpoint the issue and help you find a solution.

When you speak directly to the phone folks, they have tools at their disposal that will allow them to give you advice specific to your network and Sonos system.

At the very least, you’ll have reserved IP addresses set up for your Sonos ;)