Nothing will technically be 100% silent, including a SSD (see coil whine).
The Nextcloud box comes with a 1TB mechanical 2.5" drive, which will make a small amount of noise, but it’s hard to say if that’s too much for you or not. Most likely it will make significantly less noise than your NAS drive though.
If you consider an SSD to generally be completely silent (true for most people), there are drives out there larger than 1TB. But it depends on how much money you want to invest in it. Newegg SSD results over 1.2TB. Or if you are simply looking for ways to throw your money away, check out this 60TB SSD , but apparently it won’t fit in the Nextcloud Box.
It shouldn’t be difficult to buy the correct Raspberry Pi 3
Don’t forget, the benefit of buying the Nextcloud box is to support the developers, and because it comes with Nextcloud installed and preconfigured. If you buy your own drive, you need to install it yourself which takes more time and skill.
I don’t mind investing money. After all, I want a no-fuss experience. (I’d rather invest my time in making the Nextcloud integration on Ubuntu Phone painless as soon as the device arrives home.)
However, I’m a bit worried that the box offering feels more like a proof-of-concept for Canonical’s IoT strategy than a product targeted to (non technical) consumers. It should come in different flavors (big hard drive / small hard drive / no drive at all / external connectors or slots for SD cards, with Raspberry Pi 2 / Pi 3 / no board at all).
That may push mainstream adoption of home-hosted document storage and collaboration data. Otherwise it’s a playground for a few selected nerds, mainly. (But do nerds need pre-installed software? It could be that a few people from product development or marketing are missing the point here.)
Honestly, I don’t know a lot about the Nextcloud box, but it is a cool idea to get more people set up with their own private cloud. On the other hand, you lose out on redundant backups, and in my experience those small mechanical hard drives are about the least reliable drives you can get (they don’t tend to last very long).
I don’t know the reasoning behind not including the Raspberry Pi with the box itself, because I think you’re right that it would make it more appealing to more users, especially paired with different drive size options.
I’d be hesitant to push mainstream adoption of this product though, because of the fact that it promotes using a single laptop hard drive as a backup solution, when that really is a single point of failure. You really need at a bare minimum two drives, or better yet, a cloud backup service like Backblaze to host a copy of your data offsite (I know you lose some privacy this way, but the alternative is not practical for most home users).
Having said all of that, keep in mind you have a good support community here where a lot of people are willing to help out with setting things up and troubleshooting any issues you run into, even if you want to do something it wasn’t designed to do.
I know Nextcloud partnered with Western Digital, but now that they’re selling SSDs, maybe they could offer the 1TB SSD as an option, probably more reliable and definitely faster.