One of the biggest arguments involves the environmental impact of using cloth over disposable nappies. The waste of over 80,000 lbs of plastic and the annual use of over 200,000 trees to make nappies is wasteful in itself. While the nappies are marked as biodegradable, this only works if they are exposed to oxygen and sunlight. Plus the waste in the disposable nappies is often absorbed into ground water, contaminating clean water sources. Cloth nappies have none of these issues.
Nappies are not cheap and can be very costly each month. Cloth nappies, on the other hand, only cost the initial investment into the nappies. However, you could be spending about as much on a nappy service for laundering the items, thus making the cost discussion irrelevant.
Now that cloth nappies include Velcro strips, mothers no longer need to worry about the danger of safety pins or nappies coming undone. Yes, owners of cloth nappies will still have to launder the nappies after use but a nappy service could help with this problem. So, the convenience of the two types of nappies is fairly similar.