Before MRP's, and after Missiles were buffed, there was a period of time that the FAS was in a bad spot. With it's modest shields you'd expect to hull tank some, but missiles would just strip my weapons and send me packing. I needed to switch. The obvious answer was the FdL, not my favorite ship, but it's shields made a strong case at the time. I struggled with the FdL for a while, until the Ship Kit for the Vulture appeared.
After playing dress up with the Vulture I decided to take it out for a while. It was just what I was looking for. Agile, tough shields, and decent fire power. A shift back into the Vulture was much better than the step up to the FdL. I now jump back and forth between the FAS, and Vulture. If I'm going out to do multiple tasks, I take the FAS. If I'm just going to drop in somewhere and collect bounties, I will opt for the Vulture.