It really depends on you. I've done both, and for me it all depends on how much sleep, if any, I get on the plane. I try to avoid planning anything major though. If arriving early for WDW it seems like a good day for the hotel and Disney Springs, I don't think I'd be trying to hit up a park. Last year we arrived late, got to the Swan around 12:30 AM, crashed as soon as we could and we were up and heading to the park around 9:AM and feeling great.