Absolutely they work in Illustrator and Flash (Photoshop as well.) I work as an Illustrator designing/illustrating games and I only use the tablet as for me its more natural and efficient. Yes you also have a pressure points with those programs which you can't access just using a mouse.
Any wacom tablet will work. It's a nice investment too, it may take a little while getting used to but now whenever I need to use a mouse on someone's computer I feel like I'm pushing around a brick.
Hope that helps!
