To me its a no brainier, I would also choose the Cisco 891. My reason are simple. Most of our customers work from home. the PoE ports (it's best feature)along with the VPN/QOS features allow me to hook connect (dare I say) an Avaya or a Cisco call manger (the later being the popular choice)
I'd choose the ASA 5505 for offices of a dozen or more and the company as devices that need to be accessible from the net. IE Web Site. A good example is a realestate or doctor's office.
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