Baby stage is the easiest for me. So portable, hardly any stuff/equipment required, very cheap, everyone likes them and wants to help with them. People expect you to be focused on them and sleep deprived etc.
18 months to 5 years has been very tough with both, especially dc2 - no longer so portable, have opinions, going anywhere takes an age because they walk at a snails pace, but you have to go places because they need 'more' than they did, they cost more, they need more stuff and space and they argue about everything. People don't expect you to be focused on them in the same way, and no one cuts you any slack for sleep deprivation - even though both of my children especially dc2 slept much worse as a toddler/preschooler than as a newborn. They move things, they destroy things, and nobody wants to help out with small, argumentative, peeing on your furniture, waking every hour to shout at you, leave a trail of snot everywhere, writhing kicking angry toddlers.
5-10 has been better. Cost more again, but less stuff......more portable. More possible to do things with. But I'm yet to experience teenagers.