Final Draft is an industry standard scriptwriting software, used mainly in television and film, I believe. It's very easy for one person to use, and has excellent benefits of pagination control, name changes, and scene swapping; it runs great reports on the language and structure of the script; and I think the current versions have more tools to help with the actual writing and plotting of the script.
The way it does all this is to follow VERY strict rules about formatting. If the person working on the script doesn't know all these rules, then transferring the script to Word is a real nightmare, as above posters have said.
I can explain most of the rules of Final Draft formatting, if you want, and I've had success (though not much) in transferring the script to Word by controlling Word's Style menu. I can explain more there if you want.
Nowadays I do all my scripts in Word if I have time before prep week starts. I don't know of any easy way to add cue lines or blocking notes on top of an FD document, nor of any easy way to open a multi-page .pdf document in an application (Word, Photoshop, Pages) that will let you draw on top of it.
FD was created for writers, NOT for SMs.