I can't comment on much about the Pacifica, but it does share an engine with my van. Everything on my van, including the 3.6 Pentastar V6 has been extremely reliable in the 7 years that my van has been on this planet.
Have you looked at the Toyota Sienna? If you're concerned about reliability, the Sienna is just about as bulletproof of a van as you can buy. The Sienna seems to be priced similarly to the Pacifica, too. The Pacifica will likely have more gadgets, toys, and probably a nicer interior than the Sienna, but the Sienna has a proven track record as one of the most reliable vehicles on the market.
The Sienna should also have better resale down the road should you decide to swap out your van at some point.