noun
uneven results; mixed success
Refers to outcomes that vary in quality, sometimes good and sometimes bad. Often used when evaluating performance, work, or harvests.
今年の米の出来不出来は天候次第だ。
This year's rice harvest will be uneven depending on the weather.
彼の作品には出来不出来の
There is a big difference in quality among his works.
むら means 'unevenness' in a broader sense (color, texture, distribution), whereas 出来不出来 is limited to unevenness in results or performance.
Compound of 出来 (result, outcome) and 不出来 (poor result, failure), literally 'good results and bad results'.