The big news is that the price differential between Blue and Blue Plus tickets is generally only $15. JetBlue has made it a better value to purchase a ticket that includes a checked bag than it is to pay a bag fee, even in advance. In addition, buying a Blue Plus fare earns more TrueBlue points than the base fare, for marginally more money.
In comparison, Delta and United don’t have fares that include a checked bag, nor do they let passengers purchase checked baggage ahead of time for a reduced fee. American does offer fares with checked bag included, but the premium is more than the cost of a checked bag, although it does include group one boarding.
Essentially, if you are going to check a bag, don't book on Orbitz or Expedia and just select Blue Plus via JetBlue.com. Attention media, friends and family, it's still the best out there.