Pros:
-Bargains can be had
-Fun to drive
-Versatile interior
-Small exterior dimensions so easier to park
-Relatively fuel efficient compared to other mini-vans
-You can buy a manual transmission
-Available with many creature comforts (e.g. heated seats, HIDs, sunroof, parking sensors). Even the sport model has nice options (e.g. cruise control, steering wheel mounted controls).
-No stupid infotainment system that becomes outdated after two years
-Sliding doors
Cons:
-Smaller interior than other vans but should be fine for a family of four
-Trunk is smaller than other mini vans (becomes mini-cooper sized when all six seats are being used).
-Not as safe as full sized minivans (probably a factor of being smaller)
-Interior lighting could be more plentiful
-Watch for power steering and camber issues on 1st gen models - they are known to eat tires
-No power sliding doors (unlike many other mini vans)
Note: the fact that it is smaller is both a pro/con depending on how you look at it.
Late to the party as well, and Miami pretty much nailed everything, except for one or two things- so I will throw in my 2c.
Wife and I just had twins too. Plus we already have a 3 year old, so knew we needed an upgrade from our Jetta.
And what actually fits 3 car seats right is a short list. We really should have gone with an Odyssey or Sienna, truck space is too limited with three seats.
But our budget ruled them out. Even a quality used one (2011+ under 40k miles) goes for $20k. we got our 2013 Mazda 5 sport with 6k miles for $14500.
Other than the tight squeeze for strollers and gear when we are all packed in (it is volumeous once you put all the seats down)- I have loved it, save for 3 points.
1. Road noise.
Mazda are notorious for this, and now I know why. Have to crack up the radio so loud just to drown it out.
2. Gas mileage/Power.
Power is fine- if it's just you. Add people and it starts to struggle. Mileage, while great for a mini-van, was hoping for better. Initally held off buying, hoping the 2015 came with a skyactive, but when I saw no skyactive for the U.S., looked for the best deal I could.
3. Outdated dash.
Did not think I would mind this as much as I would, but I do. At least it has a usb/aux input.
If you are on a budget, the 5 can't be beat.
If you can spend more and staying at just two kids, my advice is to get the Mazda CX-5 or Mazda 6 with the 2.5 skyactive. Better gas mileage, more powerful engine. Both will hold two car seats and gear fine.