If you have natural gas, then that would be the better option, but the correct gas stove/gas fire will be the key decision. LPG is a good choice also but will be more expensive to run than natural gas.
DFE's (decorative fuel effect) gas fires are the ones to see away from. They will be approx 25% efficient with a lot of room heat loss when they are off.
If you choose an ILFE (inset live fuel effect) gas fire, these are excellent and approx 76% efficient. Other choices would be gas direct flue gas stoves, etc. Equally as good, so it will be down to your personal taste.
Makes such as Valor and Gazco are very good with plenty of excellent back up customer service when needed.
Another excellent make would be Jotul but pricey. Again, equally good back up service.
Just make sure your RGI ensures the flue and ventilation is correct for the appliance and if it is not a balanced flue appliance, you will require 2 carbon monoxide alarms with the appliance. (one in the room of the appliance and another within 5m of your bedroom doors).