No. None.
PrCs are bad for druids, with the only exception being if you had planned on becoming a Shifter (/Warshaper, /Nature's Warrior, /Etc) from the outset. Druid is one of the few classes they built right, where it's worth sticking with the class for the full progression of the character.
For the most part, dipping into PrCs meant that some of the druid's key abilities, like Wild Shape, become less powerful. You say that your character is primarily a summoner/wildshaper - good, stick with that. Nothing does that combo better than a straight druid does.