You want to promote your goods by comparing them to a competitor’s. EU law has some detailed provisions on this. That law has been tested in numerous cases, from perfumes to mobile-phones.
Now the top court in the EU has said it is not just a matter of taste. If food products compared meet the same needs or are intended for the same purpose, then it does not matter that they differ in terms of the extent to which consumers would like to eat them and the pleasure to be derived from consuming them; they can still be compared!
Lidl SNC v Vierzon Distribution SA (Case C-159/09) on Council Directive 84/450/EEC concerning misleading and comparative advertising.