In terms of actually ranking them:
1. Rondo
2. Big Al
3. Tony Allen
4. Avery Bradley
5. Kendrick Perkins
So two starters from a dominant world championship team(one a 4 time All-Star, 4 time All-Defense and one time All-NBA player). A guy that was the centerpiece in the KG trade. And two defensive guards that when added to Marcus Smart's time as a Celtic means the Celtics had one of the best, if not the best, defensive guards in the league, on their roster, for over 15 years.
Given we aren't counting top ten picks, where Ainge landed the best player in two consecutive drafts, that's pretty dang good drafting.