Script or prose, you shouldnn't really care what format it's written. There
are writers that can't write in prose but excel in fiction, there are some
that kicks butt in prose but their script stinks, there are the gifted that
can do both, and there are people who can't write period.

There has been many wonderful script fics and prose fics. Why should you
care what format they write in as long as you liked what they wrote?
Examples of excellent Script fics:
Putting Your Heart,
Actor in the Mirror, 
Cat's Cradle
The Elseworlds stuff

Prose:
Heart of the Home, 
ect

prose and script
Darker Half