Great points above. Have traveled recently during both times.
I tend to lean towards the Jun/July 4th dates, if given a choice between the two. We did 7/4 week last year and it was perhaps my favorite trip all year. Great vibe, fun fireworks. July, and even July 4th, isn’t quite the “mega crowds” these boards can sometimes make it sound like. Crowded yes, but manageable.
If you are talking about this summer… watch out for Toy Story Land, which opens 6/30. That could add a wrinkle to your dates this summer (although I’d be excited at this prospect…among the first to see a new land).