Just thought I would post this as my daughter is currently in London. She used Dot2Dot transportation to get from airport to Hotel. You reserve your spot online. For my daughter with two suitcases it was 19pounds! She said that check in at the airport was quick with very friendly service. The bus was very clean and the driver pointed out things of interest to them. You are guaranteed that there will be no more than three stops to let other passengers off. It took one hour for her to get to her hotel in the business district. She said that it was so nice, after a long flight to have someone waiting for you and to not have to navigate the subway with luggage. Hope this helps some people out. She found the website at the Heathrow airport web page you could also do a google search.
This kinda looks like an advertisement.....
LOL.....No really not an advertisement. I just wanted to share this bit of advice as I know how confusing it was when we were searching the web for the best way to get from Heathrow, to hotel. My daughter is traveling alone and the thought of taking two roll on bags, plus a carry on onto the subway was a bit daunting. A taxi was out of the question simply based on cost. So this is not an ad, just a Rick Steves fan trying to help another traveler.
It's great! I use them whenever I'm travelling with a lot of luggage. Otherwise, just use public transport. But, dot2dot really is the best. They're reliable, inexpensive and the staff is great. Oh and it's not a bus. It's more of a small 'luxury' minivan. There will never be more than 10 other people travelling wih you.