To me and my wife and our tastebuds, you can never top real fruit. I absolutely despise extracts and will not use them unless absolutely necessary.
If it were me, I'd use fresh strawberries. Cut them up, freeze them for a couple of days, and when it comes time to use them, pull them out to thaw for a day, place them in the fermenter and transfer the beer on top of them. I've done it this way now 4 times with zero issues. Not saying it's the right way and people will tell you you're taking a chance with this method, which you are, but it works for me.
However, if you only use carboys and don't have a fermenter with a wide enough opening, I'd suggest making a puree from the fruit and using that.