They seem to be very confident (if not arrogant) in their cook abilities, bragging to have made dishes with the most rare and expensive ingredients, reaching the amount of 1,000,000 per dish. However, they are hypocritical and fraudulent, as they came to G-8 to so-called teach the chefs there to cook better, only to reveal that their own performance is far inferior; it is unknown if it is simply the ingredients they use in Mary Geoise gave them their delusion of better cooks or they knowingly lied outright.
Despite being self-proclaimed to be great cooks, they have shown to be unable to even peel potatoes properly. This contrast is probably due to most of their cooking ability depends on the high quality of the expensive ingredients they normally use.
They only use the finest ingredients and are said to use 1,000,000 to make each meal, earning the scorn of the G-8 chefs. However, thanks to Nami they got lost in the base, with Luffy and Sanji being confused for them. They eventually find their way to the Mess Hall, but prove to be much worse than the other chefs. They did not know how to peel potatoes as they had helpers back at headquarters. In frustration, Jessica forces them to start over from the rank of "dishwasher".