Want to hear something crazy? Skype's call quality is better than our current home phone's quality, which is provided as part of our high-speed cable Internet package. It's clear, and as long as everyone on the call has high speed Internet (or you're calling a landline or cell number) there is no delay at all. If someone happens to be using dial-up or a REALLY slow computer, you'll experience a bit of a delay, but it's not bad.
As far as setup, I use my bluetooth cell phone headset to connect wirelessly to my laptop. I was using my built-in mic, but it picks up background noise, so now I use the Jawbone. Changing the Skype settings to "headset" is super easy.
And yes, it is super-cheap. We paid something like $30 USD for the entire year for Skype Unlimited, and the Skype-in number is around $20 USD.
The only real issue I see is that some services aren't offered in some places as they are a UK based company. Their website is a little hard to navigate, but once you get tot he right place, you're golden!
I really hope this helps!
P.S. The only reason we're going to have to keep our home phone is for our security system. Plus it's good to have a backup phone (in case something happens to our cell phones) for dialing local emergency numbers. You can't do that through Skype.