Having played online slots for over 2 years now, I'd say I'm pretty experienced in them. I think I can say confidently that freeslotshub is one of the best sites available, if not the best.
I can play games without having to bet real money, and this helps me to practice and actually get better at the games. Although it can be difficult to decide what game to play, they do give insights on the best slots, so that's a plus.