We love our Chariot CX2, we got mainly to commute with the our kids. But its so light and easy to maneuver that I would use to walk around and even go do my groceries with it. The back bag is impressively big enough.
Our kids are now 4.5yo and a 2yo. Mine 4.5yo is quite tall for her age, and I can see some struggle to fit both inside. So for short trips they will be fine, otherwise is a bit narrow for 2 kids at this age.
Is a bit of a pain to fold and quite bulky for a car boot (I have a Prius), so isn't practical to be used as a substitute to a pram on a everyday basis. But occasionally when we go for big walks or a trip to the zoo its worth it.
The quite expensive, specially if you decide to get the extras, but its top quality.

The Chariot CX2 is a very well engineered carrier. I really like the balance behind a bike, it tows really well behind my single speed and creates very little drag despite the total weight (with a 2 and 4 yr old).
As a jogger it is also great and the drum brakes are superb when going downhill. The kids are also very secure in the harness and there is heaps of storage.
Folds easily to fit into a car, although its still reasonably big. Great weather resistance as we have been caought in the rain a few times. Dad gets wet but kids are all good.
They are expensive with options. Re- sale is good though and ultimately you get what you pay for.