I have the TF-RTA G2 version, All i can say is, it's worth the £20 asking price! Massive deck on it that could take some nice builds, and superb airflow. The supplied claptons aren't bad either.
I also have the Griffin, the current version, not the 25. Only difference i could see between the two, was larger capacity (thanks to the wider tank), and top airflow. Neither i really need since the TF-RTA covers the required airflow, and i'm happy with the Griffin for an everyday take-to-work sort of tank.