You'll pay £22 (A$41) for one-way standard economy seating (aka Express) on London's Heathrow Express, or £30 (A$56) to ride in the first class 'Business First' carriage – so what does that extra £8 each way get you?

Not a lot, as it turns out.

It'll get you between London's Heathrow Airport and Paddington Station in exactly the same 15 minute sprint, just with a little extra comfort.

You'll be able to swap the crowded standard cabins with their 2-2 seating layout...

... for a queiter space where seating is arranged 1-1.

(Why is it quieter? As best I can figure it's partly because the Business First carriages are never as crowded as their economy-class counterparts, and also because they tend to be solo frequent flyers or well-travelled couples rather than families and excited first-time-in-London visitors.)

The Business First class seats on the Heathrow Express are a little wider, with a little more legroom.

And rather than sharing an AC or USB power socket, Business First travellers get their own plugs plus a small table.

And, well, that's about it – unless you count the scant scattering of 'reading material' which nobody seems to bother with. And why would they, on a 15 minute ride with free WiFi?

That said, there's one time when first class on the Heathrow Express is absolutely worth it – and that's when you buy a standard economy ticket but use your Star Alliance Gold frequent flyer card for a free upgrade to Business First.

Read: Free Heathrow Express first class upgrade for Star Alliance Gold

That's the card I played during a recent trip to London, and it worked a treat: I simply showed the ticket inspector my economy ticket and a Star Alliance Gold-grade card.

This is one reason it's worth pocketing a Star Alliance Gold status match whenever such promotions arise.

If you're planning a ride on the Heathrow Express, booking in advance (between 14 and 90 dayes) can yield substantial savings – and to save time at the airport or Heathrow Express station, digital tickets can be bought via the Heathrow Express app for iPhone or Android devices.

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