I got free passes to an early screening of this movie and brought my three boys - 8, 7 and 14 - to the showing. I enjoyed it and laughed more than a few times - which is all I really ask for when I see a animated movies (sans some special movies). It was not as good as the first one but it was very enjoyable.
I am biased though as I am a HUGE minion fan. I laughed every time they were on screen. Whoever came up with these guys and their voices are geniuses. I would gladly lay down money to see a whole minion movie.
Bottom line- if you like1 and/or the minions this is a must see. If you did not or do not like the minions the stay away.
Despite your meaning here, and despite the issues with the prequels of the other famous franchise Disney recently acquired, I think that recasting a young actor and doing prequel adventures of new Ph.D. Dr.