We have a love-hate relationship with US Air. We normally fly them from Philly to Orlando. The past few times that we've flown we have had bad experiences, but my dh always writes them letter explaining the situation we experienced along with possible solutions to fix those problems. Then US Air end up sending us $150 vouchers pp and then we end up flying with them again. I will fly with Southwest in a minute because their fares tend to be better. US Air we have had several delays and I don't mean 10 minutes.
From PHL to MCO it is roughly a 2hr/2hr 15 min flight. Our trip last year, our flight was supposed to leave at 5pm and arrive at MCO at 7ish. We got in at about 2am, after sitting on a plane until 11pm before we even took off. Coming home from MCO our flight was supposed to leave at 3pm, we boarded the plane at 5pm and sat there for 2hrs at the gate, we ended up getting into PHL around 11pm.
Like I said it's a love-hate relationship. If they continue to provide me vouchers when we have issues, I will continue to fly them. The first time I have to pay full price, I'm on another airline.
Good luck! (My one tip is to bring snacks to eat because when we were on the plane until 11pm before take off all they offered us was pretzels, not cool with an 8yr old and 4 yr old)
Also, the earlier the flight the better chance it will get off without a delay. This year we are flying at 7am. I know I should be at MCO before dark!