This is a great collection of Rodriguez's films, let down slightly by the lacklustre Once Upon a Time in Mexico. El Mariachi was a stunning debut, I think of it as his Evil Dead equivalent, forming the blue print for the excellent Desperado. Its worth owning for these two alone, but I guess Once Upon a Time... completes the Mariachi trilogy.
Desperado features some great action sequences, Rodriguez really has an eye for a scene. The acting is also good, very tongue in cheek and suited to the film. It also features Salma Hayek (very under used in Once Upon a Time..) what more can you ask for?