I saw a few Tivo'd adds for this stuff earlier this week and was curious enough to actually stop fast-forwarding and watch the adds. Curiously - this Pepsi Throwback product features sugar! As opposed to high-fructose corn syrup. Supposedly there is a Mountain Dew Throwback too but that's a different blog post.
When I saw an "8-pack" at Target I had to snap it up and try it.

My take: Good. It didn't seem as dark as regular pepsi and it definitely wasn't as sweet which was good. I'd say pick up some Pepsi Throwback before it disappears in a month or two.