Patio Heaters

Does anyone have a patio where they use the ceiling mounted heaters during the winter? We have a new patio and I would like to use something like these but have no experience with them. Any tips or types that work better or are safer than the others? We will have natural gas access in the roof of the patio.

They seem to break down into two primary types;

Overhead like this
Tube like this


We have had good luck with mars products.
Outdoor Heaters
George Mills