I do and it's awesome. It's super easy to make changes - they send you an email a couple of days before your stuff ships as a reminder.
I use it for lots of stuff - including dog and cat food so I don't have to deal with lugging around big bags. Once you have 5 subscriptions you get 20% off everything. (Diapers are always 20% off). Best deal ever.
DD is two and we still do S&S. You get an email before they ship things so you can skip shipments, change sizes and all that before they go to ship whtever you've set up.
Totally worth it. We have never run out of diapers in K's two and a half years of life, thanks to Amazon Mom!
When K was an infant, I did a box per month. As she got older and had fewer diaper changes, I changed to every other month. It's worked out fine. I did have some extras when she switched sizes but I donated them to the local womens & childrens' shelter so they were worth it.
I did like 2-3 months of diapers from Amazon, and then the price went up enough that I could do better locally with coupons. I was disappointed.
They always send an email alert a few days before your order ships, so you can change the size/quantity or cancel/delay if you need to, so the logistics are pretty easy.
We ended up with an extra 1/4 pack of diapers that E outgrew, and just gave them to one of H's coworkers.
E grew really quickly, and moved up in sizes faster than I would have thought. He was in a size 6 before he turned two.
The only time I've found a better price is at Target with 30% off clearance price for the case + using a coupon. Huggies Lil Movers rarely has good coupons, though.
seriously. they sort of hold your stuff so all of the subscription things that can arrive the same day, do. so all of a sudden you come home from work and it's like amazon claus has visited in his sleigh.