The Mazda5 is the sportiest of minivans since it's so small. Take note that when your kids are older they will probably want to bring friends with them in the car. The Mazda5 has 3 rows of 2 seats, so if you carry 5 or 6 people you will need to open up the tiny 3rd row seats. With a small SUV like a CR-V you have a lot cargo space and you can carry 1 less person than the Mazda5 minivan but you only use 2 rows of seats. When one backseat is up in the Mazda (to carry 5 people) there will be less cargo space compared to carrying 5 people in a CR-V. For this reason I would not recommend the Mazda5 for carpooling. It's really small inside, especially in the third row. You give up utility and practicality for nimble handling. It has less than 6 cu.ft behind the 3rd row whereas the 2011 Honda Odyssey has 38.4 cu.ft behind the 3rd row.
Other than that and road noise, the Mazda5 was underrated. They should have sold more of them. The Mazda5 only got a "Marginal" rating in the side crash test and a "Poor" rating in the small overlap. It was rare for a car to score that low in the side test. There were much safer options.
I'd suggest the 2008-2009 Mazda CX-9. It's an agile SUV with 3 rows, which is rare. Consumer Reports said the "Agile handling that masks its size is a nice surprise, as a run down a twisty back road will attest." Has much more space than the Mazda5 and is still more fun to drive than most SUVs. 2007 had an engine sourced by Ford and was not as good as the years after when Mazda made their own engine.