The biggest problem with double pushchairs is their size. They are often hard to fold and will not fit into the boots of all cars. Because of their size, double pushchairs are often quite heavy as well. If you need a compact pushchair then the umbrella style folding of the mclaren double pushchairs will probably be the most appropriate.
TIP : If you have a toddler and a baby then a possible alternative to buying double pushchairs is to get a buggy board for your existing single pushchair.
There are lots of different double pushchairs available. When buying you will need to consider what situations you will be using the double pushchair in. For example if you do a lot of walking or use your pushchair on the beach you might like to buy an offroad style double pushchair. If you spend a lot of time walking around towns where there are narrow pavements you will probably be better off with a tandem double pushchair where one seat is behind the other one. The sites listed on this page will provide a lot more information to help you choose the double pushchair which best suits your individual requirements.