TOR browser is made to hide one's identity it can be a very useful tool for the people who want to be anonymous on the internet, also TOR is highly used for dark web, but there are some limitations that i faced while using this browser was that you can have a full screen window because it reduces the security level, moreover the speed is reduced compared to normal browser. But I still love to use TOR as my current browser because the security level one can get it very rare in any other browser.

There is a large difference between using TOR only to finally exit to clearnet, and using TOR all the way to the final destination (conducting business with a fully onion site).  Exiting into clearnet defeats many of the strengths of onion.  I am talking about legal stuff not "kiddie crap".  A well constructed site running in onion doesn't even disclose where the site is physically running.  Yep, lots of stupid OPSec errors allow them to be found, but correctly setup ones remain "dark" in cyberspace.  That is where I want my LEGAL mixer to be located.  You can't grab a server if you don't know where it is.  If you think servers aren't getting grabbed by adversaries, even though they conduct 100% legal operations, you are just naive.  So yes I do use TOR.  I am inside a linux VM on TOR making this post, as an example.

Like anyone else, I'm one of those people who are so conscious about my privacy and personal identity by in the end I keep revealing myself in the eye of those who are good to it. Tor may be a good help to that but because of low internet connection in my country/place it's hard to used it daily. So I just keep myself away from suspicious activity for me not to hide anymore.

I heard that TOR is a Russian design. They had problems in Russia. I think that after this, they began to cooperate with the FSB. Probably the FSB now has the ability to monitor TOR users but if you are not a Russian citizen then you have nothing to fear.

I think you probably heard wrong. Tor onion routing was developed in the mid-1990s by the United States Naval Research Laboratory. It has been principally funded by the US government, so I would be more inclined to worry about cooperation with various US law enforcement agencies (not the Russian FSB).

Due to various vulnerabilities that were exploited over the years, and the fact that governments can run exit nodes themselves, I would not expect Tor to provide full anonymity. It can be useful, but it's advisable to use additional tools to secure your privacy.

I prefer to use AdvOR

Yes, I'm using TOR. Right now I'm abroad for an indefinite period and I don't want my identity to be exposed. I also use ProtonMail for maximum security. I'm not interested in DarkWeb and DeepWeb so I don't browse them. TOR for me is a tool which allows me to be anonymous on the Internet. I think I'm going to run a node in the future. What do you think about hosting one on OVH dedicated server?

Tor does not make you completely invisible. If your country banned the use of bitcoin then you will find. But sometimes it so happens that to find a person more than not to search at all. I think that person is easier to find then when it changes bitcoin for Fiat. Banks keep track of such operations and can pass this information to the competent authorities. In our time it is impossible to be completely anonymous.

When you hope for something that will protect you from being tracked by third party software you are deeply mistaken. If the government wants to track you they will do it. Each person must decide for themselves supports it bitcoin or not. If you support you have to be ready to defend their rights.

I'm using Vypr VPN and I am happy with it.
I use TOR only when I want to browse underground sites.