FC4 as business-class router

["Aaron O'Hara" <ajeo hungryforlife org>]

I have a client who has an office of 100 users who mostly use the
network to access the Internet.  The number of users is expected to grow
30% each year and they want to add VPN functionality.  Their current
router (Linksys) keeps requiring to be reset and I think it's time they
upgrade to a business-class router, akin to the Cisco 1841 or something
from SonicWall.  

After looking that the prices for these appliances, I was wondering if a
PC-based router running FC4 (or similar, like CentOS) would be just as
good/better/worse than the appliance?

My fear with a PC based router is that there are more chances for
hardware failure given the increased number of parts.  Do people on this
list have experience running PC-based routers serving 100-200 users for
shared Internet and VPN?

--Aaron