Hello Jen,
This is a topic you have to make your own mind up about. There is a lot of information out there about dog food, and there is also a lot of misinformation. At the clinics I have worked, both in HK and overseas, we have generally recommend Hills and/or Royal Canin, not for many other reasons than they seem to be reliable and we have good suppliers
The quality of these foods is very high. An important thing to note is, despite what people will tell you, the Veterinary industry is not funded by Pet Food companies, so we will not recommend their food for "sponsorship" reasons. Some clinics have a close tie to a brand/supplier, and will use that brand exclusively, that is their choice.
As far as Hills and the information you have read - be careful what you believe. There are a lot of anti-pet food people out there, often the same people push their own food or "natural" type recipe of food. But beware of propaganda. There are pros and cons for both processed pet food and home-made stuff, but do remeber this - pet food companies (especially Hills and other "brand names"), have spent millions in refining the foods to best suit the pet population. So unless you want to analyse your pets home-made diet to ensure your pet gets all the nutrients it needs, it is safer to buy a processed food. And, like all things, the more you pay for a product in a competitive market, the higher the quality will be. Just remeber what your dog's gastrointestinal system is designed to digest - a whole animal. It is not designed just for muscle/meat. The body needs nutrients from skin, bone, liver, kidneys, the works. To feed a home made diet often runs the risk of creating a dietry insufficiency of some sort.
As far as your dog's soft poo - as you have not changed food rapidly (as Carang mentioned - very good point
) I'd advise seeking professional advice. See your local vet very soon if the soft poo persists, as there can be many causes.
Hope this helps.