I purchased our Mazda 5 sport about a month ago with a Cash for Clunkers deal trading in a Kia Sedona. I wanted better gas mileage, and we didn't need quite as much space, but I didn't want to give up being able to carry extra people, or lots of stuff. This car was the perfect choice. I took it on a 600 mile trip a few days after I got it. We had no problem fitting my family and all of our stuff in it, and when we got there, we were able to fit the other family traveling with us in for short trips. My worst mpg so far has been 23 mpg around town on the first tank of gas. My best was 33 mpg, mostly highway driving on our trip. I have been averaging around 26 (mostly around town driving).
Sliding doors (so kids can't hit the car next to you), seat position- not as high as a minivan, but way higher than most sedans, flexibility - you can carry people, or stuff.
Bigger glove compartment (it barely holds the manual), some more storage compartments in the front (like a place to put my sunglasses), seat pockets on both back seats, another power point in front (there is only 1, so I have to have a splitter if I need my GPS and I have to charge my phone!)