Just got the Topeak HRM and speed Cadence sensor installed on the bike. Connected first time to both without an issue. (Though the speed sensor didn't work till I installed the battery)
I have an Android HTC One with OS 4.3
Tested with Runtastic Map my Ride and Topeaks Panobike App.
I believe it connects to Strava too but I have the unpaid version.
Will report after a few rides but wanted to let people know about the Android compatibility.

Those are Bluetooth LE (AKA Smart), right?

4.3 also supports ANT+ on devices that have ANT+ hardware capability, like the Galaxy S4.

Yes it is. Bluetooth 4.0. The reason I posted was I couldn't find much on HRM and speed sensors that were Android compatible.

Personally, I wouldn't quite put it that way. Bluetooth LE and ANT+ require hardware in the phone and software that supports the hardware. It's the new Android OS that's supports phones with compliant hardware, not the other way around. So it's Android 4.3 that is now compatible with existing BT LE and ANT+ hardware.