I agree with Fasttr. It depends on what you want to do and how important temperatures are.
We've been in Hilton Head the last two Aprils. In 2017, the temps were perfect for about everything - golf, beach, pool, bikes - in the low to even mid-80s all week. Great beach weather. In 2018, the weather was coolish in the 60s for all but about three or four days of a 9-night trip. After about noon, in the sun, it was warm enough most days to sit by the pool, but mornings and evenings were quite cool, especially walking on the beach a couple mornings when it was borderline cold and very windy.
If pool and beach is what you are after, then Florida would probably yield more predictable temperatures in April. I have been going to central Florida in April for a work-related event for the last 10 or 15 years, I can think of only once when the temperatures were lower than the low 80s, and that was the day after a monster cold front came through that brought tornados and storms. Within 24 hours temps were back in the 80s.
If you are looking for a more diverse vacation - bike riding, golf, great restaurants, beach/pool, boating, etc - then its hard to go wrong with Hilton Head. It is one of our favorite destinations. We've been four times this year - April for nine days, and long weekends in June, July, and October. Just if you go in April, come prepared for both warm and possibly coolish weather.