This is a good support for exercising in, but not for all day use; the integral stays on the outside of the leg rub a sore spot if it's left on all day; for all day use I find the tubular neoprene type better. If you're considering buying one of these, my advice is to see a sports physiotherapist, and/or buy a book called "Treat your own Knees" by Jim Johnson. It's a short book, tells you everything you need to know to improve "strength, flexibility, responsiveness and endurance" and no bull. It's also referenced if you want to check the original papers he quotes in the text. In fact do all you can to get this book, it contains vital information that may mean you no longer need to consider surgery, or will aid your recovery from surgery.
The combination of the physical support given by the support and the informational support of the book gave me the confidence to start exercising (gently) a painful knee when advised to rest it. Resting it made it worse, exercising it following the regime in the book, and wearing a knee support, has improved it quite substantially.