Well you can see the fireworks from either spot but both are impaired viewpoints. Plaza Inn is v near the castle of course, and the castle is the focal point of the show so you will be nearer the locus of action. However, Plaza Inn has some high hedges and trees between you and the castle (especially when viewing from a seated position) so you will miss some of the projections on the front of the castle and effects like that. French Market is all the way over in NOS so you will totally miss the front of castle effects but much of the firework activity is naturally way up in the sky, and you will be able to see that pretty much as you would if you were watching the fireworks at the ROA after a F! show.