Yes they are fun to watch , if you get one that likes to be handled ten even more so...but you need to put the time into taming for it to pay off.
Easy to keep? Fairly. I do a proper deep clean once a week, and a half clean inbetween.
They need to be fed and watered every day, as well as some out of cage time. Either in a ball or free range in a very safe place!
They eat hamster food and the odd bit of fresh veg. Treats can be anything from a piece of cheese or chicken to mealworms.
They are nocturnal so will be up at night, if you get one get a wooden wheel as these are completely silent apart from the patter of feet. I have trained our two to come out about 5 for dinner. they are about for a few hours then go back to sleep until the early hours. Yes hammy will be happy to sleep anywhere during the day
They need a big cage - minimum guidelines from the RSPCA are 80w /50h/50d . If you look around you should be able to find a good deal on one ,. but this will be your biggest start up expense!
They are great pets but I always think they are more of a adult pet than a childs..... have you thought of Gpigs? They are fab for every one! 
We are on our second hamster and have 2 GPigs- however, they are mine . Not ds's, not a family pet, mine! This is ultimately because I know I would be the one looking after them. I would not get a pet, even when ds is 18 and wants one of his own, unless I want it too!
If you are not pre-pared to take hammy ( or any other pet) on if/when your ds gets bored then don't get one!
Good news (or bad news- whichever way you look at it) is their lifespan is quite short at 18months - 2/3 years.
Our girl lived til 22 months and I was devastated when she went, but ds did deal with it very well.
HTH :)