All in Twos are very popular among cloth bum parents. What makes them great is that you can have 3/4 inserts per shell and just change the insert each time. This keeps the cost down and reduces washing. It also means that the drying time is usually pretty good as you can detach the inner from the shell. All in Two inserts are usually hemp, cotton or bamboo or any combination of the above as these materials provide the most absorbancy. All in Two nappies can sometimes be slightly bulkier than All in Ones. Resale value is usually good depending on condition. The draw backs could be that nappy changes can be a bit more tricky if you haven't already got one prepared and you need to change the insert during changing.