0-1 was a complete shock as I had no clue what to expect with a newborn. Being around other babies here and there in no way prepares you for having your own baby 24/7, LOL! I had no clue what to do, why he was crying, was sleep deprived, etc...
1-2 I knew what to expect, so it wasn't such a shock to the system. The hard part is the lack of sleep. When you only have 1, you can nap when they nap, and try to catch up on sleep. When you have a toddler, you can't nap throughout the day to catch up. You just remain sleep deprived and get on with it. Life is busier with keeping up with both kids. But even given the sleep deprivation and busier life style, I still think it was easier going from 1-2. At least I wasn't completely clueless when I had my 2nd!