Yes I have that. I also have the Ultimate Polish. Both are very nice as far as results are concerned but I personally prefer the Ultimate Polish over the M7 - it is easier to apply and is also more abrasive, hence can clean some paint defects.
M21 is a totally different product as compared to M7 - it is much less shiny than M7 but much more durable. I currently have M21, M7, Ultimate Polish, Black Wax (for my Black CL9), White Wax (for my Red Civic Turbo) and Pinnacle Signature Series II.