Hiya Cass
The question you ask is...
So Rog, what's worse, adding some keyboard work to a midi file or playing a three-finger chord that sounds like a full orchestra. I love my arranger; it gives me a lot of versatility, but a good midi file is more like the original song.
My reply is
What is better than either of your proposals is using a special rhythm/style file, playing live, that sounds exactly like the original song, and you're playing it - aah but where do you get them from I hear folk say....