I drove (from East London) to Heathrow this morning rather than face the long schlep via the Piccadilly line (I'd usually use the HEX). Was a bit worried that I might get stuck in the usual traffic at Kings Cross/Marylebone but the roads were pretty much free flowing and it took me 1 hour door to door (or rather door to pod parking).

I only ever drive to Heathrow over the Christmas period when there's no HEX. Unfortunately it seems to be becoming a habit! The Piccadilly doesn't feature as an option for me - ever since years ago I missed my flight after my Piccadilly train broke down.