i fail to understand why you are so happy that the heat transfer from an electric element to water is more "efficient" than a flame on the bottom of a pot??? Seems like an irrelevant point to me...
it is all about cost - how much does it cost to boil 10 gallons of wort for an hour or so??? here in southern California, i did the math and the increase in cost for electric brewing was somewhere around 8-12 dollars per batch (for me - your electric rate could be different).
I went with NG and have observed the cost to be nearly negligible. Granted, if electricity were cheaper, i do absolutely concede that using Electric has many advantages - quiet, less waste heat and no issue with carbon monoxide. Creating an electric brew rig i think is somewhat more expensive and risky if you do not absolutely know what you are doing. That said, i wish i could go electric, but my sensibilities with cost pushed me to NG.
so for me in Southern California - it is NG.
Cheers!
Jim