We own six weeks of timeshare in Ft. Lauderdale and have been vacationing there from late January to early March for dozens of years. Whether I am out and about alone, or with female relatives or friends, I have never felt fearful, nor have I ever encountered any dangerous or criminal event. (Our age range is 50-92).
I personally feel that Ft. Lauderdale has improved greatly over the past 10 years. Tourism is their main industry and the police presence and enforcement of quality of life crimes is excellent. I no longer see homeless people wandering around--not that they really caused much harm when they were more visible years ago.
Like any large city, there are neighborhoods where poverty and criminal activity are problematic. But these are small and self-contained pockets, far removed from the tourist area.
I'm sure you will find much to love and enjoy in Ft. Lauderdale. I hope, however, that you are not expecting to find timeshare availability during Week 7 which is President's week.
We own at the Ft. Lauderdale Beach Resort and find the location and amenities to be excellent. If you love the beach, this is the place to be. You could make do without a car. Just take the $10. per person shuttle from the airport and then use the extensive public bus and water taxi system to go far and wide. The upscale Galleria Mall, plus tons of restaurants (all price ranges) are within walking distance or a short bus ride away.
This is in no way an "ad" since we use our units every year. But it is an 18 story building with hundreds of units and is the one you would most likely find as an exchange through RCI or I.I. if any are available.
The three huge Vacation Village timeshare properties (Weston, Bonaventure, and Mizner) are very nice and can have good exchange availability. But they are far out on the western end of Ft. Lauderdale, about 25 miles inland from the beach and theatre and cultural center of Ft. Lauderdale. I think it would be far more difficult to mange without a car out there. And car rental rates are very high in February unless you book 9-12 months in advance, which is what we always do.
Enjoy your vacation. And don't worry about crime or safety issues.