A Single Board Computer as a home network server?

I do all of that and more on a little Intel Atom 230 today and it's proven to be more than capable.  You're right to think that it will be more work to get things running on an Arm board (any arm board), but if you're ok with Debian then most of them have access to some variation of Debian already. Other distros can be more troublesome.

Today I'd say the only real reason to go for an Arm board is if you want to reduce power consumption. Once you've made that decision you then have to decide on what compromises in performance you're willing to make to meet your power consumption goal.

The one thing to keep in mind when looking at Arm boards is that they typically don't have lots of memory, so full desktop distros with all of the junk they drag along for the ride may be wasting what resources are available. Especially things like mysql and subversion will do better with more memory. If possible I'd suggest moving your version control to git, I find it's generally faster than svn and uses less resources and so performs better on lower end hardware.

The last thing to note is that a lot of the Arm boards want to have the OS booting from SDcard. If you're at all interested in performance, try to avoid that. SDcards are usually optimised for very different uses than general OS boot disk and can be a real performance limiter. I've finally got several embedded boards booting from SATA and the difference is amazing.

As Morgaine says, boards with gigabit ethernet & sata are few and far between. Then, depending on where in the world you are, you find it can be less than easy to source them, or that a notionally $100 board becomes $300 by the time it gets to you.  If the cost of the Arm board exceeds a cheap mini-itx Atom, then you have to start seriously examining what the reasons are for chosing one.

I do all of that and more on a little Intel Atom 230 today and it's proven to be more than capable.  You're right to think that it will be more work to get things running on an Arm board (any arm board), but if you're ok with Debian then most of them have access to some variation of Debian already. Other distros can be more troublesome.

Today I'd say the only real reason to go for an Arm board is if you want to reduce power consumption. Once you've made that decision you then have to decide on what compromises in performance you're willing to make to meet your power consumption goal.

The one thing to keep in mind when looking at Arm boards is that they typically don't have lots of memory, so full desktop distros with all of the junk they drag along for the ride may be wasting what resources are available. Especially things like mysql and subversion will do better with more memory. If possible I'd suggest moving your version control to git, I find it's generally faster than svn and uses less resources and so performs better on lower end hardware.

The last thing to note is that a lot of the Arm boards want to have the OS booting from SDcard. If you're at all interested in performance, try to avoid that. SDcards are usually optimised for very different uses than general OS boot disk and can be a real performance limiter. I've finally got several embedded boards booting from SATA and the difference is amazing.

As Morgaine says, boards with gigabit ethernet & sata are few and far between. Then, depending on where in the world you are, you find it can be less than easy to source them, or that a notionally $100 board becomes $300 by the time it gets to you.  If the cost of the Arm board exceeds a cheap mini-itx Atom, then you have to start seriously examining what the reasons are for chosing one.