We've now lined up for FoF three times and we've seen it twice.
1. April 7--about a month after opening. We snagged a curb spot in from of the Emporium near the corner of Town Square. It was a Monday and we sat down a little after 2:00. Since the parade was new, we didn't want to take a chance of not getting a good spot. It started to fill up around 2:30. The few was not excellent because we were constantly looking down the street toward the castle and the view of the floats was obstructed by other guests even though we were in the front row. Also, the floats are so large that sitting and looking up from the curb does not provide the best angle.
2. May 15--we used the reserved handicapped accessible area in Liberty Square. If you're using this area, still arrive early because the space is finite and the day that we were there, it did pretty well fill up. It seemed like the view here would be ok (not great, but ok), but unfortunately, there was too much of a chance that the rain would start again, so the Rainy Day Parade ran instead.
3. May 17--we got a spot in front of the train station on the ground level at around 2:30. The necessity to get there so super early for a spot seemed to have declined from April, but it was also the Saturday of Star Wars Weekend, so the results may have been skewed. Once again, we were able to secure a front row spot, but everyone around us was standing and that made for a much better vantage point. These floats are very tall for the width of the street, so I would definitely recommend trying to find a place where the street is wider and you can stand in the front row without people getting angry at you. The best thing about this spot was that we could see the floats turning the corner, so we were able to take photos straight on and from the sides.
We also thought that up on the train platform would be a really cool vantage point for this parade and we've had good experiences watching parades that start in Frontierland sitting on the planter boxes in Liberty Square--but you have to be EARLY to get that spot!