The only problem I’ve had with Raspberry Pi is that some apps want to write a lot of stuff to “disk”, and the default “disk” on a Pi is a MicroSD card which dies if you keep writing things to it. Sure, you can always plug something into a USB slot, but that adds a bit of friction to the whole process.
Oh, also, I wish it were easy to power a whole bunch of Pi units. Each one needing its own wall wart is a bit annoying, and I’ve had iffy results using weaker, less steady power supplies with multiple ports intended for things like phones.
They take up so much space though.