In extract brewing half the job is already done for you, instead in all grain brewing you can deal with other things that will make you have a more accurate control on your procedures as well as a much more personalized beer. Mashing is the basis with all its details you have read in books and although you`ll have to manage a lot of detail (temp. control, enzymes, pH, sparging) and some extra hardware don`t let these things drive you mad, it is all a matter of brewing batches, reading and asking for advice. Here almost nobody brews with extract (they are expensive and hard to find) so we all started all grain and believe me There are great beers.