Coincidentally, a family member of mine has recently stayed at one of each of those hotels, so enjoy a tiny sample size of data:
The Hilton they went to used Mifare Classic, clonable to either of those implants
The Marriott used Mifare Ultralight EV1, which isn’t directly clonable to any implants right now
In my experience, and from what I gather of other people’s, Mifare Classic is one of the more common cards across various hotels
There shouldn’t be any really appreciable performance difference between the xM1 and the xMagic, it’s just whether you want one chip or two
If you haven’t read it already, you should check out this thread, which should help explain the differences between the gen1a and gen2 chips.
Long story short is that either should work for you if you’re using the PM3 though
If maximum performance is more important to you than the pain of waiting an indeterminate amount of time, you could wait for the FlexM1 to make a reappearance, it would perform much better than an x-series implant in terms of range