Vice Admiral/Lieutenant General Ship Token: Speak with a Starship Requisition NPC to claim a Vice Admiral (Fed) or Lieutenant General (Klingon) ship. For Federation characters, this token can be used to claim an Exploration Cruiser Retrofit, Long Range Science Vessel Retrofit, or Tactical Escort Retrofit. For Klingon characters, this token can be used to claim a B'rel Bird-of-Prey Retrofit, Varanus Fleet Support Vessel, Marauder Patrol Cruiser, or Kar'Fi Battle Carrier.
I would have to go with the Kar'fi - and of course I get the Vet ship too. I don't like switching ships around and I often take my KDF toons into a STF elite. I don't think the B'rel would last very long or be very effective - come to think of it I don't think I have ever seen a B'rel in an STF elite!