I have it working on all my 3 devices, Mac,iPad and iPhone all updated to the recent software update. My only problem is when i have a new photo it takes hours sometimes days for all to sync. I have strong Internet connection. Thanks.
Welcome to more! That is normal, although 'days' is a little excessive. If you want to get a photo from one device to another more quickly you can always Airdrop it to yourself.
Google photos work on iPhone and iPad. Might be a better option for you. Best part of having an iPhone is you can still use other services and get the best of both