Isn't that unlimited outbound only for Skype? Don't they charge separately for inbound calls?
I had those dinky MagicJack devices, and while it served a basic purpose for $40 a year, I didn't want the software sitting on my desktop, especially knocking it out whenever my machine wasn't logged in or in the middle of a reboot. So, I picked up an Ooma for $160 and been pretty satisfied since, with unlimited inbound and outbound, and I was able to port my old telco number.
On this note about the software on your desktop. There is a product out called the Nettalk Duo. It is the same type of thing as the MagicJack, but no software as it plugs directly into the router. Slightly more expensive, but from what I have heard it actually has customer service and they are supposed to be a little better.
Myself I use a MagicJack but its hooked up to a computer being used as a headless file server so, I never have to look at it.