In my experience, NICU or PICU is so much better than any floor nursing. Here's why I think that: In PICU we only get 1 or 2 pts. They are really sick, of course, but you can see them at all times! One reason why I didn't like the floors was because you can't see your pt.s unless you walk into the room! It is easier in critical care to ask another nurse for help, everyone is right there in close proximity.
In NICU, the pt.s are small, so you won't break your back. In our NICU we can have up to 3 pt.s, sometimes that's busy, but not as busy as floor nursing.
Just remember you have to deal with a lot of parents, which can be stressful while you are caring for their sick baby and they are so worried about everything. Yes, NICU nursing is alot different than the floor, it's still busy, but in a more manageable way...IMO.
And, last but not least, baby bottoms are a lot smaller and easier to deal with!!