Internet web filters like Websense and iPrisim get more sophisticated every day. They can easily detect proxies as soon as you try to use them. They can even read your email, check for proxy links, and block them before you have a chance to use them. The most advanced systems can block you within seconds.
The name of the proxy, how new or “fresh” it is, whether it’s https or not does not matter. The proxy will be detected and blocked because it’s a proxy. All proxies are the same and all can be easily detected and blocked. There is no one proxy that is better than any other.
There is a huge risk in using free proxies from unknown sources. Many of these free proxies are what are called hacker pots. They are there waiting for you to fall into their trap so they can steal your personal information, login credentials and plant bots on your computer. Once a bot is planted the hacker has control of your machine and can steal credit cards, attack web sites and send out tons of spam all from your IP address.
Some of these free proxies/VPNs are run by people out to simply make money and not by hackers. There is nothing really wrong with that in principle. However the best case here is that you will get a proxy loaded with advertisements with no real speed to it. The amount of money the owner can make with advertising clicks is really only pennies a day per user.
Many of these owners supplement their income by key logging everything you do and selling your personal information to advertising companies. Some very well known free VPNs and proxies do exactly this and make a lot of money in the process. Unfortunately for you, the global databases with your personal information keep growing as you use them. Before you know it anyone with the money to buy the information can get a complete profile of you and your thinking, your buying habits, opinions and more. These databases never go away and will follow you all your life.
Since you have no way to know what the owner is actually doing you need to assume the worst case is true.