"You have a book."
Translation:Jij hebt een boek.
There are no differences, besides on personal preference. Both "u hebt" and "u heeft" are correct. For hij/zij, almost always "heeft" is used, but you can sometimes hear "hebt" in spoken language as well. For "jij", only "hebt" is correct.
The reason, as one Dutch language organisation states, is that "u" used to be the third form (hij/zij/het/men) which almost always uses "heeft", but nowadays is considered more to be second form (jij) which uses "hebt".
I would say it's a clear 50%/50% in usage here.