I use washable nappies. I don't find it too much of a hassle tbh. I use tots bots nappies. Just stick them in a bucket with a net, then when it's full chuck them in the machine. I stick a bit of napisan in with the washing powder as it seems to help with the smell. If you can line dry them even better, as the sunlight bleaches the poo stains when they are really little, so they come out white again! My nursery agreed to use them as well. I've got about 25ish tots bots which is about enough, I've got a few Closer too which I use if I've run out, but they are not as good IMHO.
Downsides are they are bulkier to carry round with you, you need wet bags to carry the wet ones, you are always doing washing, what with baby clothes too. Have to change them more often than a paper nappy. Might not be cheaper if you are planning to use childcare who won't use them.
Upsides are cost. It does work out cheaper, especially if you are planning more than one child, and it feels cheaper to me. I spend about £180 on 20 nappies, a bucket, couple of nets, few other bits from the baby show. Then I buy the napisan, liners, had to buy a few wetbags, but the running costs seem small. They seemed to leak (poo) less than paper when he was new born. Obviously less waste and environmental impact.
Hope that helps!