I always take the Tube from Heathrow. Easiest (yes, I’m a guy and have learned to travel pretty light!) fastest and cheapest, not to mention often highly entertaining! Only time I’ve ever almost missed a flight from LHR was last time when my boss insisted I treat myself to a cab. There’d been some hazardous waste spill on the main motorway that afternoon so London traffic was even worse than usual — and the trains were not affected! lol
Which reminds me… pack my Oyster Card for next week’s trip!