Yes i`m agree with lupo89...i rode the RRZ-09 for 2 years, and it was very funny. Balance, stable and if u play with forecarriage and with wheels u can gain agility in "tight corners", that usually u cant do easy with RR.
But here atm...the most popular chassis is DM. It is less stable than RRZ, but more more "supple", fleet, agile.