Hi Draoi - this can greatly depend on the country you are buying in - can you let me know where you are considering?
The main benefits usually relate to savings in income tax payable on rental income for that property and CGT savings on the disposal of the property at a future date.
The downside is that there are additional costs involved if purchasing through a limited company: 1) the purchasing/set up of that company; 2) ongoing tax returns for that company where the services of a local accountant will normally be required.