When we visited London a couple of weeks ago, we used the Heathrow Express to and from Heathrow.
Using the Heathrow Express saves time compared to taking the Tube all the way to Paddington/central London, since it doesn't make any stops between Heathrow and Paddington (it does stop at two terminals in Heathrow). It takes 15-20 minutes from Heathrow to Paddington Station, and trains typically leave every 15 minutes.
The Heathrow end of the train is easy enough to use. There are people explaining how it works and selling tickets. I had bought our tickets online ahead of time (it saves a little money, but I wish the tickets could be added to Apple Wallet), but there were machines where you can buy tickets. You need to scan your ticket when you enter and exit the train tracks.
We got on at Terminal 5, and there were lots of seats. We grabbed a couple and were even able to charge our phones at an outlet on the train during the ride.
It's pretty easy to use, and I'd definitely use it again when I'm next in London. read more