Tā de dòngjī wúkěfēiyì, dàn fāngfǎ zhíde shāngquè.
His motives are beyond reproach, but his methods are open to debate.
Tips
usage
Softer than 无可挑剔 ('nothing at all to pick at' = flawless). 无可非议 just says 'no grounds for blame' - often implying 'acceptable' rather than 'outstanding'.
mistakes
Don't confuse with 无可厚非, which means 'one shouldn't blame it too harshly' - implying there IS a minor fault, but it's forgivable. 无可非议 = totally fine; 无可厚非 = forgivably flawed.
