I was thinking along these lines last week.

For a leisure traveller going into London for a bit of fun, I flew to LGW and enjoyed the superb domestic seats in CE configuration up the front, was served by the most charming of cabin managers, took the FCC train to London Bridge and swapped onto SouthEastern to Charing Cross...and that only took 40 minutes from leaving Gatwick and is every 15 minutes and is cheap.

In fact, in every way apart from the lounge and possibly newer planes (right enough the moving map is about the only benefit of a new plane), LGW beats LHR for me.

Of course, if connecting abroad or travelling in F, it has to be LHR.