Tails , the anonymous operating system

I tried the Tor browser, which makes the user anonymous online, which means the website you browse doesnt know who you are wont be able to track you . but it requires the user to change lot of browsing habits.
and associated link with the tor browser was their operating system,Tails. This is a Debian based operating system and tries its best to not to leave any trace of users activity. And each time boot it ,its like a new operating system.

I tried it by making a live USB of tails. And even if i install software, when i shut it down , they are destroyed. It allows the user to create persistent partitions to store data or setting permanently , but i don't know if that it safe.
Has any one tried it out?
does it have loop holes?