Never done it myself but there are quite a few doing that route this month, fares into Jax were about half the fares into MCO. I believe its a similar distance as Miami to Orlando, about 3 hour drive, I wouldn't hesitate at the right price.
Just booked for next Easter 29th Mar - 12th Apr into JAX got it for £382.21 each. As already mentioned MCO coming in about £460 and TPA nearly the same.
Just going to check out the airport website to see the facilities, I already checked car hire was on site.
On my Nokia maps its 2 hrs 50 mins and Google maps 3 hrs 12 mins to where we normally stay.
Never been to JAX before, but "if the price is right" I'll go anywhere.
It's not a bad drive at all. The Speed limits are high. You could make it in about 2 hours. There is really no chance of getting lost. Its a straight route.