Strawberry (and other berries) really are tricky. In fresh fruit, the sugars ferment out leaving a tartness behind without all that much fruit flavor. Think of a strawberry, and why you like it. Then picture it with the sweetness gone. It's tart, unpleasantly so, usually. Raspberries are even worse, as they are more acidic and so when fermented out they can be very tart. Many brewers then add lactose to help bring back some of the sweetness.
Strawberries can be good in light, tart-ish beers. Picture a strawberry wheat or a cream ale with some strawberries. Extract is sometimes better than fruit in beer as it has the sweetness and flavor, both, in it. Of course, some extracts aren't very good and a fake fruit taste is worse than the tartness.
That's why I said it's tricky. I've only done a few fruit beers (best was watermelon wheat), but I'm a winemaker and go through this with many fruit wines.