Interestingly I have not needed to use any mixing services so far in my 2 years of cryptocurrency life. In fact, I do not find the importance of using them. With bitcoin, I already feel I am secured and anonymous. Maybe in future I may need one, then surely I will start testing from bitblender.
The need of mixing services is highly depending on the level of privacy/security you are expecting. Some of my friends are just using mixing services to protect themselves from some wallet services for not showing that they are into gambling.
When you will be in need of a mixing services for whatever reasons, I recommend you to start with cryptomixer, a great services in my experiences.