I believe an important factor is whether this is primarily for heating or ambiance. We have natural gas powered logs in a traditional fireplace (not using any sort of insert), which requires the damper to be open while burning. So it provides a fire but a lot of the heat is lost. It will barely keep the room warm. An gas insert should be a lot more efficient than an open fireplace but when compared to an air tight electric system energy costs may even out, leaving it down to a question of looks vs costs.
I cannot put myself into your situation or preferences. Personally I consider gas logs as fake as electric when compared to a traditional fireplace, but I understand that most people including myself would prefer looking at a real flickering flame anyway. But when considering the costs and bigger picture of this being for show more than heat (in my house) I would also have a bias towards an electric unit.