200GB subscriber here, shared between wife, son and myself using Family Sharing. Works a treat for backing up all of our iOS devices and for having full resolution offsite backups of all of our photos going back years, together with photo syncing across our macs and iOS devices. Being able to store full resolution photos in iCloud and having optimised (ie down rezzed) photos on our devices has cut down on the storage requirements on individual devices.
We’ve found it ‘just works’ (we were MobileMe family pack subscribers beforehand, going back to 2004). We also locally back up the macs with Time Capsule so we’re not wholly reliant on iCloud for our only copy of photos in the event of something going wrong.
Together with our @mac.com email addresses and now with iMessages in the Cloud, the £2.49 GBP per month price is very good value for money.