IMO, the Buran system was superior.
Take the shuttle off of the stack and what's left? A large tank and two booster rockets. Take the Buran off of its stack and what's left? A fully useable super heavy launcher. Even the zenit boosters can be used as launch vehicles in their own right.
The Energia/Buran platform is a modular launch system. It's a regular one stop shop for opening up the entire solar system.
