We stayed at the Hilton Heathrow on the night before we flew out to Dubai ..
What a great location, a short walk via a rather chilly tunnel to the centre of terminal 4
We parked our car in the car park just 30 yards from the hotel lobby
The rooms are very clean and have everything you need, it's very quite considering the runway is no more than 100mts away from your bedroom window, there was also no noise from the other guest leaving for flights all through the night, which is very unusual at airport hotels ..
We paid £165 for the night and that included 8 days parking which we feel is great value for money.
We ate in the airport terminal as the prices in the hotel were rather exspensive
This hotel is perfect for customers who don't want the hassle of picking up buses when they have returned from a long flight to get to their cars , just a short walk from the terminal ..

Perfect ..

everything here was spot on from the moment we arrived until we left
we lacked for nothing and the service and standards were impeccable!

we especially liked the concierge,alan, was outstanding and made us feel right at home
and was very kind and gracious to our lad- great place!

This was an end of the long, active trip and we were tired, hadn't had the best of beds and were ready for a little pampering. This was a very good choice. The bed was heavenly, the little refrigerator drinks welcome, the clean and lovely bathroom a pleasure. For our last night the location was super, right next to terminal 4 at Heathrow. We just walked our bags in and caught the terminal train to our concourse. Oh, the muffins the next morning in the coffee shop were wonderfully fresh and tasty.

I will try and keep this short.
Plus point the location. As my partner was traveling from T4 it was an obvious choice. The hotel is directly connected to the terminal via a covered tunnel. It takes only 5 minutes to get to T4 so booking in was a dream. It also means that you can eat in T4 rather than spending 'daft' money in the hotel itself. Reasonable choice and only 5 minutes away and dont forget to stock up on essentials like water as it will cost you £4 in the hotel. Although the downside to this is that you are forbidden to use the mini bar to put your own goods in. If you do they will charge you - or so it says on a forboding notice on the front of it. I also fail to see how a small box of pringles can be £4.20 and a tiny tiny bottle of wine (187 ml) be £10.00. It really is just to much to pay. If you can try and get yourself some little milk pods as you will only get four and you need at least two per drink (it whole milk too - does anybody still drink whole milk in tea yak!)
I can imagine that when this was first opened it was fantastic however it now a few years old and it shows. The furniture is tatty and damaged. The chair was stained and worn and the wall behind the beverages was stained with splashes from the many cups of tea etc made there. The bathroom although it was clean was showing its age with the grouting in many places having turned a curious bright orange colour.
As somebody else said the windows are triple glazed and it does seem rather claustrophobic and the air con is bonkers when its on you freeze; off and you perspire alot!
The staff were not tremendously enthusiastic or welcoming rather too business like for me. Although the concierge was very helpful so big thank you to him. He actually engaged in a conversation. The odd thing was the express check out. You get a note passed under your door in the night telling you how much extra they have calculated for your stay and that you can just put your keys in an envelope and put it in a box at reception. Did they not want to say "goodbye" or "did you enjoy your stay"? Seemingly not i personally think that a bit sad and taking 'express service' one step to far.
For £189.00 for one night i thought it was absolutely NOT value for money. Not sure of what your options might be but if you are happy to get a shuttle/taxi to T4 from another hotel then save yourself the money and use them. Sorry to say i have to go back in four weeks as i've already paid for a room when i return to pick my partner up. Teach me to be so hasty.