As has been mentioned, there's a lot of factors to consider :
1) How far are you from the nearest airport? How far are you from a US Airport with cheap flights to Orlando? How many people are flying? During the fall, you can often fly return from under $100USD/person
2) How long are you planning on staying in Florida and how much time do you have and how valuable is your time? Although it can be done from most cities in the Eastern half of Canada in 24 hours, for most people it's a 2 day trip there and back (although by the time you check-in, go through security, get your luggage, you're probably looking at 6-8 hours or more to fly direct - easily 12 if you have a connection) so that might be most of a day. Adding 2 days at both ends of your trip makes a 6 day trip into a 10 day trip. For us this is a small but not negligible issue as I don't have tons of time off.
3) Does anyone in your party have issues flying? Does anyone in your party mind spending 2 days in the car? Since we typically make the trip in our motor home, I do all the driving. I have no problems being on the road 12+ hours / day and driving 2 or 3 days straight. Our kids are okay with it (our youngest kind of hates it but they play video games and watch movies the whole time so he doesn't really mind it. our oldest loves it and will usually be perfectly happy looking out the window (even on the Interstate) and if he's not looking out the window, will gladly play video games. My wife hates it and is annoying the whole drive! If it wasn't for the convenience of having her on with her during the drive, I'd have her fly and pick her up at the airport.
4) Factor in all the costs? Driving means gas, hotels (can be quite cheap) and meals (likely significantly more than the hotel) but you have to factor in some long term maintenance cost as well (you'll be driving 5000 kms in all). But you might want to drive around Florida so if you drive, you don't need a rental car (probably $50-100USD per day).
5) Do you want to stop anywhere else along the way? For many tourists, Florida is the destination but there are tons of sights to see along the way. We typically really only care about Florida but we've stopped many times at many places (Myrtle Beach, Hilton Head, museums, aquariums and air shows along the way, we've often thought about stopping at amusement parks along the way but it's only happened once (Diggerland USA in NJ which our kids loved)
Our situation is someone unique in that we have a motor home and rather than leave it in Canada during the winter we drive it to Florida in the fall, leave it in storage there so that we can use it a few times during the winter (on oldest is in grade 9, our youngest is in grade 4 and we're not close to retirement). We typically make 3 or 4 trips to Florida between the Fall when we drive it there and the Spring when we drive it back. Our costs are also kind of different since 1) we are travelling in a motor home so we usually just stop overnight at
Walmart along the way (this is actually a convenience thing since we have a campground membership so can often stop overnight for free but it's just more convenient to stop at Walmart) and we eat all our meals in the RV so no extra cost. The fuel costs are significant though (about $500-700 each way) which is more than we usually pay for flights. In all, we'll usually spend 6+ weeks per year in Florida so having the RV and our car there is very convenient (enough that we actually have a 3rd car that we leave in Florida over the winter simply because long term, it's cheaper than renting for 6 weeks.