I've experienced both sides of the coin more than once - restored a project car myself and bought someone else's completed project for less than half of what they had in it. There's merit to both ways and it all depends on how you like to spend your time and money.
If you're handy with tools and have the work space, live the dream and restore a car. Just don't plan on driving it and basking in the glory of appreciative bystanders for a while, perhaps a long while.
On the other hand, if you want to drive the car anytime soon, buy one that someone else has completed as I did with my Porsche - bought it, washed it, entered it in a national show, and won 1st place. Can't put a dollar value on that warm fuzzy feeling.
A year ago, I pulled the '71 Z that I bought new off the showroom floor out of 15 years of storage. It took about a month to pour more money into it than it cost when new. My son and I are still working on the body work and interior as he prepares to get his driver's license. Can't put a dollar value on that feeling either.
Dennis