As the ladies above have noted, this is personal preferrence.
Not all resort photographers are terrible. But most certainly aren't cheap. For instance, at the resort where I got married, you got 10 free wedding photos (6x8 in size). if you wanted digital negatives, it was around $20 a photo. To put together an album alone you would need 80-100 photos, so that's $1600-2000. And honestly they aren't the best quality.
Now, photographers IN the area. Wow. There are some AMAZING photographers in the Riviera Maya. Seriously, A. Mazing! There are also some who are not so amazing. But Elizabeth Medina, Del Sol, Juan Carlos (Cabo)... these are some of the best. They too aren't cheap. But you honestly get what you pay for when hiring photographers in the area, and these ones are great!
Flying photographers in... this is where it gets tricky and it's not always the "you get what you pay for" idea. Sometimes, yes. But sometimes photographers just like photographing in beautiful locations. Or want to grow their portfolio, so will give you an amazing deal. Typically this will run anywhere from $2000-5000+ (including travel). It really depends on the photographer and their fee. But, wouldn't you rather pay $2000+ for FULL wedding coverage (full day coverage, trash the dress, full resolution disc of 1000 pictures) versus paying $2000 to a resort photographer and getting 100 kind of not so good photos of your wedding day? What's a better value??