Choice of a proxy server is not an easy task because there are plenty of them on the internet, and each of them has advantages and disadvantages. And a choice of one of them would depend on many factors. Firstly different proxy servers are suitable for different tasks. Some of them are good at hiding your IP address, while others can greatly improve your security. Also, the choice of a proxy would depend on a client because some of them are suitable only for big companies and not for individuals and vice versa. Moreover, do not forget to consider that some proxy servers are for free while others could cost some money. So, the choice of a proxy would depend only on your demands.