I chose others to help concentrate them all in a general category as I break this title down for you.
1. Best
The best security will be the one "Best" for you, meaning fits your needs, uses, and system requirements.
2. Privacy
This part is actually an illusion. There is no such thing in the Internet.
Making purchases lets say, from your bank card, your bank sees what you bought, your ISP sees where you are shopping and what you are looking at, the website you purchase from views what you are looking at and buying and the ad companies embedded in the searches will as well. Even your security will see what you are searching as it analyzes your traffic.
To be honest this is no different then going into public to a store, where your neighbors see what you are putting into your cart, the cashier sees what you have chosen and again your banks or credit companies see what you purchased.
Privacy is a matter of divulging. Be picky about that latter part and use good judgement.
Speaking of good judgement, apply this to the best security as well, learn good habits so as to not have to rely on the security as much.