Strengths: Very easy to manoeuvre and push around. Very well balanced, which makes it easy to steer, and it's fantastically easy to push around - the pneumatic wheels really make bumpy terrain or curbs very easy to handle.
The seats are pretty comfy for the children, and recline well so you can have a baby asleep in one and the toddler upright and alert in the other.
The accessories we've got - the sun and rain protection - are good, especially the sun protection which can be covering one side but not the other, so again the children can have different options.
Weaknesses: Because the handle is a bar rather than two handles, there's no obvious place to hang the shopping.
The basket that goes underneath the chair hangs really quite low, and sometimes gets in the way when you're folding it up.
It's not as easy to fold up as some of the other double chairs.
Overall: We trialled several doubles, and this was the most all-round one we found. (We don't like the one-sits-in-front-of-the-other doubles, which is just a preference).
Strengths: Given it's a full-on all-in system , it's remarkable easy to manipulate (fold up, open), and is very comfy for the child.
Weaknesses: The sun shade is cumbersome, but not compared with any other model - more just I find the detachable sunshades annoying in general, especially when wanting to fold the chair up to stow in, say ,a car boot.
Overall: Thoroughly recommend it as an all-in system - we have the attachable car seat which has worked wonderfully for two children so far.
Strengths: It's a strong and sturdy bike which my toddler son tries to pedal on his own, and which I can push using the extendable handle behind it: it can therefore be used both as a "puschair" to take him down the road, or as an independent toy for him to push / pedal around at his leisure.
Weaknesses: For the first few days I couldn't get him off it, so I had to feed him his meals on it (no joke!).
Overall: Highly recommended as an introduction to the independence of pedal-power!