A mixed bag; a situation where good and bad things are mixed together (four-character idiom).
このサイトのレビューは玉石混交で、参考にする際は注意が必要だ。
The reviews on this site are a mixed bag, so you should be careful when using them as a reference.
大会の参加作品は玉石混交で、優れたものもあれば改善が必要なものもある。
The entries in the competition are a mixed bag; some are excellent while others need improvement.
文化祭の出し物は毎年玉石混交だが、それが面白さでもある。
The festival attractions are a mixed bag every year, but that's part of the fun.