How often does your network disconnect? Sure, it would be great if the backend storage system was better at handling atomic operations, but I don't think this is really a huge problem assuming you're not using a really crappy network.
I run Calibre with the library mounted from a NAS. Works fine for my ~2000 book collection. Not as speedy as local SSD, but it is ok.
Does that work okay with multiple machines connected at the same time? I've been worried about what happens when there's a write conflict to the DB. I'd really like a way to easily share and manage my eBook library from both my laptop and desktop.
If I recall correctly you can have the actual database file on the ssd while the books on the network share that would probably improve the speed a bit.
I run Calibre with the library mounted from a NAS. Works fine for my ~2000 book collection. Not as speedy as local SSD, but it is ok.