we chose the Mamas and Papas Twin Aria, which is very light to carry and incredibly easy to put up and down. Suitable from birth and is a side by side pushchair. Slightly narrower than some, so fits down the aisles in most shops. However, I found it very difficult to push when I had my toddler and baby in it (easy with just the baby), the uneven weight made it quite tricky (probably ideal for twins). I normally have the wheels on 'swivel' rather than fixed, don't know if this has an impact.
So, it has a number of points to recommend it, but be aware of the frustration that can be experienced pushing.