Weightwatchers foods aren't too bad, and they are one of the better alternatives as far as preprepared foods. Mostly the problem comes in with high sodium and sugars to make it palatable and extend shelf life.
When you say you aren't able to cook, you mean you don't know how, or don't have the facilities for it? If it's the former, I would recommend just getting a recipe book, and finding some dishes that you would like to try. Figure out how to cook them, because fresh food is always going to be better than prepackaged.
One of the tricks that I use is that I will spend an hour or two on the weekend cutting up veggies, grilling chicken, etc. That way during the week if I need a quick dinner I can take a pita, dump in chopped up chicken, chopped up veggies, and some tzatziki that I get from the store, and I have a tasty quick dinner.