It has always been sold as 3 class and normally operates as 3 class, given the limitations of the LGW fleet. Moreover I suspect Flub class only operates in the JFK - LGW direction on very rare occasions to help out JFK in times of need, as a general rule. Whenever I see "is it worth it", there can only be one possible reply: you tell us! It's a value judgement and subjective to the nth degree. But the one question that could be asked is whether you have another opportunity to use the GUF?