Heathrow vs. Gatwick

Which ever is the cheaper airfare would be my answer. My experience from the West Coast has always been a cheaper airfare LAX rdtrip to LHR. Others may have a different experience.

Where are you staying?

Not sure yet but saw the distance difference between the 2 airports and wasn't sure if people had a better experience flying into one than the other.

First, there is no Tube to Gatwick. There are trains which you can use your Oyster to pay for and then connect somewhere to the Tube. Not really a problem.

Even though most everyone hates Heathrow, I would fly to/from there due to there being multiple flight options almost anywhere you want to go. Gatwick is smaller and offers fewer options. I have never had issues with flying or connecting at Heathrow. BA has a direct non-stop from my home town to Heathrow so I try and take that whenever possible to reduce the number of connections I need to make.

As always It depends......on where your accommodations are located.
If your accommodations are near a tube station Heathrow would seem to be the better choice as there is a line from Heathrow direct into the city and the entire tube system.. Gatwick requires a train ride into London where you could then catch the tube. It all depends on where you are going. More details will help us help you with a better more complete answer.

If London is your destination, and connecting to somewhere else is not involved, then I vote with Claudia and let your wallet and the schedule decide

Add to above: trains from Gatwick directly serve about 8 central London rail stations, so taking the tube may not be necessary to get to your hotel: you may be able to walk from one of these stations.

Need to know where you intend to say really to give any meaningful advice; arriving in the 'wrong' one could be inconvenient although not a disaster.

You are asking for extra advice beyond the Oyster card. What kind of advice?

I prefer Heathrow over Gatwick even though Gatwick is closer to me. I just find Gatwick to be tired and dated and, at the risk of sounding a snob, because a large number of package holiday flights depart from there there is a greater number of the type of people who think that it's fun to down five pints of lager at six in the morning simply because they're going on holiday.

Ultimately I let price decide for me but as we usually fly BA or Virgin we pretty much always use Heathrow.