The bulk of Scotland's population lives
within one hour of both EDI and GLA so from a passenger's point of view the airports are complementary. EDI has more business connections (banks, government bodies) so if my clients want to visit I always point out flight availability from both airports even although I live in Glasgow.
easyJet and Skyscanner both allow searches from 'Central Scotland Airports' for outgoing flights so we have the best of both worlds thanks to competition between the two airport operators