The plots are completely different, however...the feel of both shows are the same. They both have a vibrant, lively feel that makes you wanna smile the whole time. Not to mention they are both absolutely hilarious. So, if you liked the comedy aspect of The Grand Heist, I think you will enjoy Woochi.
Both are historical comedy and involving swindling and thieving.
both movies center on a heist that seems impossible to pull off.
both feature a team of experts recruited for the heist
they have the same vibes (in that the grand heist is a historical movie and collectors revolves around ancient artifacts)
both are entertaining and heartfelt at the same time
From the same director/screenwriter, both movies are historical comedies set in the Joseon era that center on a group of professional 'outlaw' experts in scheming and deceiving.