When making comparative claims to an unnamed generic competitor, even with humor, NAD will require you to substantiate your superiority as to all major competitors. Some advertisers feel naming a specific competitor is riskier and they will more likely be challenged if they call out a particular brand but the substantiation burden may be higher if they do not.
Case in point is a recent challenge by Allstate to Progressive ads where the adorable quirky spokesperson, Flo, is discussing the numerous discounts Progressive offers that "A. Nother Insurance Co." does not. Allstate argued that a reasonable takeaway from the ads is that Progressive is the only significant competitor that offers the same benefits. Allstate asserted it had all of the same discounts, such as safe driver and loyalty price breaks. Progressive said the ads were not comparative to a real competing insurance company but instead the A. Nother Insurance Company was just a generic straw man. Even if there was a comparative message, it was limited to a claim that Progressive offers a combination of features that some other insurance companies do not offer and this message is substantiated as compared to some smaller regional carriers. They said there was no suggestion that the benefits were unique or any reference to "leading competitors". And finally Progressive asserted that Allstate was not a primary competitor in the direct channel, as its business was sale by agents.
NAD found that A. Nother Insurance Co. could reasonably be interpreted as an actual Progressive competitor. And further, one reasonable takeaway could be that Progressive offers services and benefits that its major competitors do not, regardless of sales channel. The NAD concluded that while all of the claims were supported if monadic as Progressive did offer all of the bundle of discounts advertised, they needed to be modified to detail the specific insurance companies not offering the discounts or discontinued. NAD went so far as to find the entire commercial comparative including statements like "and I get great service" to be a claim of service superiority.
So when making comparative claims, don't be afraid to name names, at least in a clear and conspicuous disclaimer to provide yourself with some insurance or consider whether a powerful monadic statement will be all the coverage your brand needs.