I travel on business regularly and know a lot of people who do the same. I can state quite categorically that as a business traveller I do compare Easyjet with the legacy carriers and along with many others have moved from the legacies to Easyjet for many flights.
I can also say from the evidence of my conversation with other business travellers they do not perceive Ryanair in the same manner.
Whilst I accept the above is not scientific I personally believe that Easyjet's comparison of themselves in the advert to British Airways is exactly the correct course of action.
Also I actually find the advert quite amusing.