I have found that the level of difficulty ebbs and flows according to a number of factors. Age of child is probably the most important one. 0-4 months is very difficult, 4-9 months is easier, then it gets difficult again as the child gets mobile, with the level of difficulty peaking around 18 months - 2 years of age, particularly if said child is what I like to call a "runner." In my experience, things start to get calmer around age 4, and after that, I can't tell you. I'm still living it.
Having two children only further complicates things, as you are dealing with different ages, and different levels of difficulty, at the same time. My kids tend to yo yo off of each other in terms of who gives me the most trouble. For a long while there it was Braden (see post about his hitting phase) - he gave me a serious run for my money for a year or so, until he slowly became cooperative, accommodating, and the most loving kid in the whole world (see post about the sweet nothings he whispers into my ear). Casey, on the other hand, was our "angel" baby, until he wasn't anymore (see post about his transition from angel child to slight terror). He hasn't yet grown out of this "terror" stage, and his terror is now, sadly, directed at other children who dare to come within two feet of a toy he has claimed as his own. But generally, he is getting more manageable. He is no longer a runner, he sometimes follows direction, and overall he's just a joy, so I can ignore the other stuff.
The boys' first official day of school was today. It was anticlimactic, really. No tears. No separation anxiety. Just hugs and goodbyes and anticipation. Their new schedule means that I have my mornings to myself - from 8am-11am. Three whole hours. It is the first time in five years that I haven't had anyone to answer to for a regular, set time period. To say it is freeing is an understatement. I can go to a doctor's appointment without worrying about child care. I can watch the Today show. I can get some work done. I can play the suburban housewife and shop at Target and get my nails done. Or I can just lay in bed for a couple of hours. The luxury of it all!