I’ve been using PVOutput for about 18 months and during that time it’s been very reliable, I can’t speak for backup and recovery and what the long term viability of the site is though.
I use SBFspot and this stores data in a local database on the Pi. You could back that up to some cloud storage but you’d need something else to query and present the data. I’ve not investigated this so can’t say if such a thing already exists.
Bob.