AIOs are as easy to use as disposables. They tend to be a favourite with husbands and creches / childminders as well as mums who are busy running after other kids. The disadvantages are that they tend to be more expensive, and many will take longer to dry as they're all one piece.
Set up: You don't need to do much to set up an All-in-one nappy. Everything is always attached and connected as it should be. Some brands have a flap that is attached but needs to be put into a pocket. You can add additional boosters and some have the option to snap these in.
Change: This nappy is easy to put on - similar to a disposable nappy. Close the nappy with velcro or snaps.
Laundry: The entire nappy is washed each time. There is no option to reuse any of the nappy before washing.
The entire nappy will need to dry together since inserts are sewn in. To allow nappies to dry more quickly AIO nappies will have some way of opening out the absorbent part of the nappy to air it: some will have flaps others layers of fabric that can be separated. Some brands will dry faster than others. If you opt for slow drying nappies you will need to buy more nappies for full time use and you will need more drying space. Nappies can take 8-24 hrs to dry. Most AIO nappies are not suited to regular machine drying as PUL and elastic cannot be separated from the inserts.
Inserts and Boosters:
Inserts are attached to the AIO nappy so it's important that you select nappies with inserts you are happy with. Boosters of your liking can be added to AIO nappies and some will have the option to "snap in" boosters.