Many homebrewers start with these type of kits, and the fact is that you can brew pretty good beers with them. Of course, your results will not be as good as if you were using one of Midwest’s recipe kits, or brewing all-grain, but you will get better beer than a lot of commercial beers you can buy.
The most important thing, and this will sound strange, is that FOR THE LOVE OF GOOD BEER, DO NOT FOLLOW THE INSTRUCTIONS ON THE SIDE OF THE CAN!! Most of the canned hopped malt extracts will instruct you to add table sugar to the boil. While this will add alcohol content, it will result in a cidery, winey flavor that is not very palatable. A better idea is to use two cans of the hopped extract, or add some DME (Dried Malt Extract). This will produce a much more drinkable beer.