Great Zimbabwe is definitely worth visiting. It's interesting you mention Great Zimbabwe because my grandmother's people came from Great Zimbabwe and brought some of the building skills with them.

To answer your question, well Bumbusi is in the Hwange National Park which is largest game reserve in Zimbabwe. Whilst the ruins might not be spectacular it's a great place to see animals in the wild. It's also on your way to the Victoria Falls if you coming from great Zimbabwe. Hope that helps.