I don't think it matters too much, they both seem to function fine. It's actually finding restaurants with reservations that becomes the problem.
Entire thread on the frustrations of ADRs at
Disneyland:
https://www.disboards.com/threads/h...ining-i-mean-for-the-love-of-churros.3838905/
Just know not all restaurants will be available at 60 days out. They seem to release a random group of dates for a random group of restaurants over a random period of time.
Also, when checking for reservations, be sure to click the specific time blocks, not just the generic breakfast, lunch and dinner options. Sometimes clicking the time block multiple times will cycle through various reservations.
Just know the process is terrible, but the end reward is really good food. We were there 2 weeks ago and most of our dining was with table service restaurants.
One final point, most if not all restaurants have a walk up wait list, so if you don't get what you want in ADRs, be sure to check in at the restaurant early in the day and get your name on the list. I'm not sure how it works, but I think you just need to be ready to eat when you're notified by text.
Good luck! And enjoy your planning and upcoming trip!