I'm sure the staff are great at LGW, but to be honest that would not be a reason to pick LGW over LHR. Schedule (is there actually a flight from the airport to the place I want to go), timing (at the right time) and price determine where I fly from. So yes, I'm doing LGW less because no longer are there BA flights to the US hubs (esp DFW), and GB Airways is no longer either. On the other hand I chose LGW over LHR recently to fly to GVA (a combination of timing and price). Now in the past BA used to fly this route, but this time I had to go with easyJet.

I'm going to SJU later this year - but I'm forced to go via LHR and MIA because the BA schedule to SJU is useless for me.

Oh, and I live also 20 minutes from LGW - so LGW is much more convenient and predictable - no possibility (Certainty ) of traffic jams round the M25.