Buran/Energia was in many ways more capable, and powerful than the Space Shuttle. Buran was certainly inspired. However, Soviets knew how to get into space. They improved the design considerably.

Buran doesn't use integrated reusable engines with the external tank, so there's no awkward mix of solid boosters. Plus, Buran has a fully functional emergency ejection seats for all crew members. More so, the Buran had automated flight from the outset and meant that Buran could be lauched without anyone and be landed fully automatic.

Energia could be launched by itself, and carry about 100 tons which is about 3 times the shuttle's capacity, and being a seperate system makes so much more sense than the booster + fuel tank mix of the Space Shuttle system.

In general, Buran, from an engineering point of view, was a fantastic piece of work and although might have been inspired by the Shuttle initially, it definitely improved on the Shuttle design.

It's truly sad that the Buran was discontinued only after one flight. It deserved more time in the sun to shine.