I will only do the 6AM if I am confident I can secure my hotel room. I will sometimes book a day room to catch a quick nap and shower then continue on for the day. Some will say to power through the day and not take a nap, I disagree. If I get even just a one hour nap it makes the rest of the day so much productive (for me at least). It can be very difficult to wakeup though. If I arrive at 11AM'ish, I still get a nap but instead of starting the day at around lunch time it is more around dinner time. In the end, it is really dependent upon the type of trip it is and how much time I have and hotel choices. I am flying from the east coast so the flights heading east are pretty short and difficult to get much sleep on, particularly the ones that arrive about 6AM.