BestDay is a shuttle service, like SuperShuttle in the US. You wait for other passengers to arrive and then you get dropped off in rotation. You might get lucky and be picked up last and dropped off first, but maybe not.

If the OP is traveling with his family he might prefer to have a van waiting for him to travel directly to his hotel. There are many very good, very reliable services operating from CUN, and there are threads on this board recommending several.

I have used AGI Tours in the past and been happy with them. I will be using them again next week. Their rate is approximately $75 US from CUN to your Playacar hotel. I don't know if this is steep, average or cheap.

Have fun in PlayaCar!