I bought a Wiser kit 2 to replace my GEO Cosy system as GEO are withdrawing support for Cosy.
The Wiser hub was easy to install as a direct replacement for my Drayton 522 timer. I initially has difficulty getting the thermostat to talk to the hub. Wiser customer support were helpful and I got it working.
It’s taken a while to get used to the Wiser app as it is different from the Cosy app but the Wiser tutorial videos are helpful. I am pleased to be able to switch my hot water remotely. The system works fine throughout my 3 storey house . I plan to install a couple of smart TRVs in a week or two. Beware of rushing to buy lots of smart add-ons without calculating the pay back period.
Overall it is “so far so good” - I don’t yet know about reliability or battery life etc.