FWIW, we have done it both ways (a 5:00 ADR at Tony's the 1st year and grabbing something in the parks the third year). I really think it depends on your traveling party and what you want to do. If you have younger kids, or people who are going to be ready to hit the party running (you know the type - go go go!), then grabbing a quick bite might be better.
We enjoyed sitting at Tony's and people watching. It was our first year, so there wasn't a plan during the party, per se. Just a general idea of what we wanted to do and which parade we wanted to see (we opted for the early one). By the end of the meal, our son (who was 5) was getting antsy. But it was still a great evening!
The best time we had was our 2nd year doing
MNSSHP, when we ate at the resort (Cape May), and then headed to the MK. We were more relaxed, and excited about getting to the park, instead of having to break stride because we were trying to agree upon a quick meal or sitting for an extended TS meal with all of the distractions of the Magic Kingdom. We also began opting for the late parade - less crowded - plus you are able to ride lots of rides during the first parade!
Hope that helps!