The 90's era Cannondale's were harsh riding; the 80's era Vitus were flexy, is flexy a problem? it wasn't for Sean Kelly who one the TDF on one including a slew of other races he won on the same bike, he didn't seem to complain about it!
Vitus has superior looks over the Cannondale, has more of a vintage look as well, and it has a glorious history behind it. Find some period correct components for it and you would be styling. Cannondale made so many of the exact same looking bike it's difficult to tell what year of a bike you have, with Vitus it's pretty easy to tell. Vitus had some bonding issues when they first came out and for the following 3 years, after that they were solidly bonded. If it were me I would go with the Vitus.
Adrenalin Bikes still sell the 979 NOS! but they cost more than what you're looking at,
https://www.adrenalinebikes.com/stor...oductid=126276