We have done two of them, both at Magic Kingdom - Tomorrowland Terrace and Garden Plaza. Our kids were 2 and 6, for first Tomorrowland Terrace; and then 6 and 10 for Garden Plaza.
Our experience was that we enjoyed the Tomorrowland Terrace better, which is why are doing that one again in May. The Garden Plaza was a bit cheaper, but we felt that we were fighting for our spot on the grass, with others pushing and moving the entire time. Tomorrowland Terrace, same desserts as the Garden Plaza, but no moving to the grass. We felt this had a better view, although it wasn't directly centered. No biggie, as the view was over people's heads rather than looking through people. Also, the view of Tinkerbell was the best at the terrace! She flew right over our heads.
Also, a thought, since you have the one year old, if I remember right, you have to park your stroller outside of Tomorrowland Terrace. If that's a concern at all, I would research about the stroller accommodation. I know we had one last time, but my daughter was much older and could last through the fireworks.
What a great surprise!