I stay at heathrow on business regularly and did try the comfort inn one. night...parking can be a bit of an issue if you are arriving late.
The rooms themselves are average, clean and comfortable but the bathroom was tiny. The hotel does have a gym though and the lounge area downstairs is cosy.

I can think of nothing good to say about this hotel.
The staff are unpleasant, the rooms are cramped & uncomfortable and the whole place feels grimy. Even the water coming out of the taps is brown. There is constant noise from the heating/plumbing system & I found it impossible to get a moment's sleep.
Normally, I think we are more inlcined to be forgiving of airport hotels, in view of the fact that it is generally just for the one night. However, one minute in this place would be too long.
I had an early start (thank goodness) & left a letter of complaint at reception. I did (eventually) receive an offensive and unhelpful response from the management. I would say that if the manager has this attitude it is no wonder that the place is such a mess.

We were looking for budget accomodations near Heathrow, and booked online. This hotel has seen better days, and doesn't match the basic Comfort Inn level seen in the states of a basic, but clean room. The room was not clean, and the furnishings shabby. They did serve a nice breakfast, but at highway robbery prices! It is convenient to Heathrow, but I would find something better in the area.

I stayed here for one night in August because it was the cheapest hotel near Heathrow. The quality of the hotel was reflected in the price. my room was incredibly small with pretty grubby carpets and fittings. The car parking was also a nightmare. I arrived at 9pm and was directed to park on the pavement as there was no space in the car park.
Not a great hotel but then you definitely get what you pay for!