For me it's power issues. I've had two Raspi4s die on me (ssd/sd card corrupted) and I think each time it was due to an ill-timed power outage or momentary power dropout.

So Raspi4 + UPS is probably maybe okay. Just underpowered and overpriced.

Mini PC + UPS def robust and reliable.

Old laptop w/built-in battery just about ideal for people that just want to keep things simple.

For data backups, my strategy is moving toward:
* virtualizing containers via ProxMox
* dual mini-PC ProxMox cluster
* nvme system drive in each mini PC
* 2 TB ssd data drive for each
* 8 TB mirrored NAS spinning hdds storing scheduled backups from the 2TB data drive AND the ProxMox container image/snapshots.

So any system nvme can fail, any 2TB data ssd can fail, and either of the physical mini PCs can die and I'd still be able to rebuild everything as long as one of the mirrored hdds survives.

And all of this is kind of just tech ops LARPing as I really don't need this level of redundancy and failover. I don't run LN so the vast majority of my node data is totally unimportant (lost my node data? Meh, IBD again).