I have seen four films of him:
Dos hombres van a morir (Ringo: The Lone Rider): Routine average movie without some surprises and ideas. A little too American for a SW, but you can watch to without getting headaches.
E continuavano a chiamarlo figlio di... : A real waste of time. Boring experiment, the Zorro theme to transfer in the Spaghetti Western.
Garringo: Very good film, with interesting characters and good implementation. For me, the best SW of Marchent so far
Uno a uno sin piedad (One Against One... No Mercy ): Bad film, where I fell asleep.
Maybe I have the Possibility to see again, to form a new opinion. But I have very bad memories.