Upon arrival at Heathrow with probably 4 suitcases would it be easier to just take a cab to a central hotel in London or take the Express ? What cost differences are we talking ?
You are looking at significant cost differences. It has been a while since we used a cab but the fare will be in the range of 50 pounds -- $100. The Heathrow Express to Paddington is around 15 pounds, maybe 16 or 18 plus the cab to your hotel. We used it last Sept but cannot remember the price. The tube will take twice as long and is the range of $10 but it works if close to your hotel and you can easily manage all of your luggage.
How many of you are there? Consider a private car service. For one person it will be cheaper than a taxi all the way and probably about the same as the total of the HEX to Paddington plus a taxi from there. For two or more people it will be much cheaper than the HEX + a taxi. Many people on the Fodors board recommend www.justairports.com. There is a discount for paying cash. Expect to pay a minimum of £30 to a central London hotel (more for a larger vehicle). Note what the site says about the carrying capacity of each vehicle type. Saloon = sedan. Estate = station wagon. MPV = minivan.
If you are just the one with four pieces, definitely splurge for the minicab booked in advance. Two or more you could probably swing it but you'd save a lot of hassle if you hired someone to greet you at the airport.
I made the mistake of moving to London and thinking I could carry three large items on public transport. NEVER AGAIN! It is worth every penny!
You could try the express bus to Victoria station from Heathrow and then take a taxi ...a shorter distance.........a bit easier than lugging the bags on the train and not as expensive as cab....
We did this in May with my 76 yr old Father and it worked out quite well......
Beth's suggestion is a good one. The National Express coach (bus) from LHR to Victoria costs £4.