Tube is ~5 I think, and bus even less. But the expensive train (15GBP, still much less than $99) gets a lot of advertising and is in all the guidebooks, so many people assume it's the only way to go (plus it's owned by the airport so they try to guide you that way). I've never known anyone who'd book a car, I once took a taxi when the tube broke down and I was running late and it was GBP30 to go ~3 miles. That seems like the preserve of the super-rich.

FWIW, I've done both trips (tube vs. Heathrow Express) and I much prefer Heathrow Express.

When I travel it's usually for business and the time savings of the Express vs. the Tube just makes it a complete no-brainer for me.

People often complain that it's a very expensive and very short train ride but they forget that the short travel time is a FEATURE.

It's not a short time because the train's fast, it's short because it's not very far. And the claimed speed advantage is based on a somewhat gerrymandered definition of "central london".

The express is sometimes worth it, but it very much depends on where you're going; the express simply dumps you out at Paddington which does not have great onward connections. Whereas the Piccadilly line, being a tube line that goes right through the centre, can often take you directly where you want to go (particularly as a tourist) - Piccadilly itself, Leicester Square, Covent Garden, Kings Cross, ...

None of this matters much to me since I'm often staying someplace close to Paddington and/or Mayfair. If I'm not staying there, I'm off to Canary Wharf and it's a taxi ride no matter what.

If you're fine with lugging baggage up and down the tube stairwells, then fine by you, but I prefer the Express for any number of reasons and time of travel/distance traveled isn't the sole determinant of my choice.

If you're staying near Paddington then sure, it makes sense. But for going to Canary Wharf the tube option is pretty nice - just change at Green Park (step-free since the rebuild) to the Jubilee line.

> Why does international flight mean 2 full suit cases?

Certainly 1 full suitcase?

Shirts, pants, socks, underwear, perhaps a suit or two, and a pair of extra shoes? I can easily fill a suitcase with that stuff.

Do you do laundry on your trip? That would certainly significantly reduce the quantity of clothes required. Now that all airlines are charging per bag (previously all airlines allowed two free bags) it probably makes more sense to figure out how to wash clothes abroad than to lug around a lot of extra clothing.

Take a little jar of soap and wash out the stuff that needs washing out. For a 2 week trip, I'd admittedly typically check luggage though. A lot depends on the details of the trip and the climate.