soekris + openbsd server buy question

[shwegime]

Hello, I'm considering buying a Soekris net5501-70 and install OpenBSD on 
it to make myself a small server and use it as a proxy (ssh tunnel), it 
might serve as backup file sever as well. I guess at the most there will 
be two-three computers connnected at the same time, and there might be 
some streaming video going through, like the videos you find on online 
newspapers. I have googled around, and read that this kind of hardware is 
fine as a router but not so much as a server. Is it true?
Thank you for any 
suggestions.
I was also considering using a netbook for the task. What 
about it?
Thanks in advance.