I stayed three nights at the Days Hotel Hounselow. It's major advantages are that it is close (three tube stops) from Heathrow and very near the tube station. Oh, and it is very economical for London (although I noticed three or four budget hotels in the area with similar advertised prices). There is not much to do in the area but there are several inexpensive places to get a meal. The area seemed safe. I did not eat at the hotel but I watched a couple games in the bar. The Bell pub (5 minutes South of the hotel on foot) has acceptable Thai food.
The room was okay but as a few people note, the carpets definitely need to be updated. Probably a paint job is in order too. But the wc is clean and modern. I don't like the doorless shower--too difficult to keep the water inside!
If you are not in need of luxury and don't mind the 35-50 minutes it takes to get to central London, then this is a good choice. Would I stay again? Maybe--the ride into town does get boring.More