Yep, in some way, yes they are similar; but not always. My notes mostly are combination of To Do(s) and thoughts, key decisions made at meetings/conversations etc.
BTW, I'm using 10C To Do on my iOS and Due Date functionality did not work as it should be. Though I selected a couple of future dates from the Date wheel and set, the date shows in the To Do summary is today's date. Not complaining, but thought I'd keep you informed :)