Note that it's not totally free, they do still have that resort fee (and the list of things they give as justification is total BS to me). But, of course, paying only the ~$28/day resort fee is a lot better.
And sure. So, I have really bad balance/vertigo/motion sickness issues. I've flown in the past, and it's about a 50/50 proposition if I make it okay or if I get really sick. Last year I flew to WDW, my first time flying in about 8 years, and I got so sick on the flight that I was out of commission for the next 2 days. But flying home was ok. Go figure. Even when I make it ok, I still need a very large dose of Dramamine at a minimum, so I'll be sleeping the rest of the day after arriving.
So I can gamble on losing a couple of days of vacation from flying, or I can just take a little longer in the train, step off in Orlando, and be totally fine. And the train is not that bad, I'm very lucky with the timetables. It leaves here in DC at 7:30 PM. I board, have dinner, go to sleep, get up, and have breakfast, then it's only a few hours until we're there. If it's on time, it reaches Orlando at 1 PM. Last Sunday, unfortunately, we were delayed with freight traffic, so we got there about 3 PM. Still not too bad. DW flew on Sunday - got up at 4 AM to get to the airport for a 7 AM flight, got to MCO at 9:30 AM, and got to the hotel by 10:30 AM. I met her a few hours later, and I was definitely more well-rested than she was.
For the return, the train departs Orlando at 1:30 PM, so we had time to do a few last things in the morning. Got back to Union Station at 7 AM the next day. So yes, it is longer travel time, but I make it healthy and ambulatory, which is not the case with flying.