They are not "hard" to take care of, they are just different. They are not a fuzzy cuddly creatures that will beg to come out and play... and they have spikes on their backs which may bother people with sensitive skin.
Hedgehogs are very slow to warm up, some never really even warm up to their owner of years. They are not aggressive in the sense that they will go out of their way to bite you.. instead, they will take any chance to run and hide in a dark spot, away from you.
Many owners are able to socialize their hedgehogs in a way that the hog is less upset by being handled and awoken. But if you expect a really close relationship with a hedgehog, you will more than likely be disappointed.
The draw of having a hog for me is the mystery of the relationship.. Every day (night, actually) I reacquaint myself to my hedgehog and slowly handle her. She is about a year old now, and is much less fussy when i take her out. She still runs from me when we play on the ground, but when she is done playing for whatever reason, she does come toward me as if to say "you can put me back now".
You must be careful about feeding a hedgehog. The internet is full of contradictions in terms of what is okay and what is not okay to feed a hedgehog. A general rule is, they are omnivores, so you have to try your best to vary their diet. They need good protein, not too much fat, and enough fiber if the fat content is too high. You have to introduce them to any kind of fruit or vegetable you can to see what they like, and experiment with cat food, dog food or unseasoned cooked meats like lean steak or chicken or turkey.
They also like bugs, but in America, the soil is tainted, and you should only feed hedgehogs store bought bugs. Hogs love meal worms and other worms like silk worms. They might also like crickets and grasshoppers.
Many hedgehogs find what they like and stick with it. Case in point: my hedgehog Izzie. She refuses any/all fruits and veggies I have offered her. Instead, she eats 3 kinds of cat food (one variety is very high in fiber to substitute her dislike of fruits and veggies), meal worms and silk worms. Because Izzie does not get a lot of fiber (she just refuses!!), I rarely give her worms. Worms are more like treats because as they are store bought, they are loaded with fat.
Your hog will need a wheel big enough and sturdy enough to support his/her weight when running. The cage should be large too, at least 18 inches (1 and a half feet) wide and 24 inches (2 feet) long. THe bottom of the cage cannot be wire- it must be solid. The type of bedding you use depends on your own research, and the needs of the hedgehog. Some hedgehogs have respiratory problems as a reaction to bad bedding.
Hogs need toys, constant source of water, and complete darkness at night. i use a blanket that I keep partially over the cage at day to keep it dark, but still open for ventilation. At night, I never leave lights or the tv on.
Hogs need a bath once every 2 or so weeks to prevent mites or dry skin. Some hogs even loose their quills, so bathing them with the right stuff is important. At the general store, you can buy bath powder for babies (can be used for pets too, so gentle on skin, so moisturizing).. Only get the powders that are fragrance free and are made from oatmeal. Run a luke warm bath in a shallow sink, mix in some of the oatmeal powder, and plop hog in. Make sure hog can run around with his/her head up- the point is for the hog to be able to touch the ground.
YOu will also have to cut the hedgehog's toenails from time to time to ensure that they can run on their wheel with out discomfort. Long nails also capture feces under them.. something you don't want them dragging about on the carpet when you let them out. Some owners cannot cut them, so either find a pet-savvy friend who knows how to clip nails, or visit a vet who will take a small fee for a weigh-in and nail trimming.
When letting a hedgehog run around, make sure they do not find hard to reach spaces behind furniture or appliances. LIke I said earlier, they LOVE and constantly look for a dark place to hide, and they will stay there until you either get them out or leave them alone. They may also chew on wires or anything else left on the ground. Pick up access food particles and laundry.. They chew on things that smell good, and might drag them across the floor. They might also be attracted to metal objects.
that's all I can think of for now