The RCBS partner press has a aluminum frame which is not quite as rigid as the lee challenger presses aluminum frame from experience the partner press frame twists when full length sizing 30-06 cases the lee challenger presses frame doesn't twist when doing the same operation but I have heard of the aluminum linkage on the lee press breaking so thats not news to me. atleast the RCBS partner press has steel linkage so you wont have to worry about that happening. either way dont waste your money on either of those.