Originally Posted by ATOBTTR

The question you should be asking in the DL forum is if DL C+ is worth saving $40 over B6. And many of the responses you get may be biased because we regularly fly DL (especially where B6 isn't an option), and many of us will just naturally go with DL in a scenario like this even if B6 may be better in some/many ways because we would rather credit to a program that will then benefit us for our many flights where DL is the only option (or at least where an airline like B6 isn't) as well as benefiting from things you may not (like SkyClub access). I.e. in this case, (without knowing schedule options) because DL is already $40 cheaper, going with DL would be a no-brainer for me and many other DL FTers so I/we could credit the elite miles (MQMs) to DL, among other benefits. If the scenarios were even reversed (DL was $40 more than B6), I'd still probably go with DL for the same reasoning - crediting to the Skymiles account. That's not to say I don't have a threshold where I'll go with another option if DL is way more expensive, but those benefits and earning the MQMs to ensure future benefits will drive me to pay a premium for flying DL over flying as a non-status passenger on another carrier.

If you care about status on either airline at all, that could be a factor. Your profile notes AA - you can now credit B6 flights to AA and get AA AAdvantage miles and EQMs/EQDs/ I think AA is even running a promo where you can get bonus miles for taking an AA or B6 flight to BOS or JFK (I received an email about this from AA recently; not sure if it was targeted).