According to the Fritz documentation, in the Sparring Mode the engine plays a reasonably strong game, but at the same time makes tactical errors. If the program finds a move that allows the opponent to gain a tactical advantage in a clever way, it will play that move. It is a very realistic human style, the kind you encounter in a chess club, or so it says.
You can select the level of difficulty of the tactics that will be offered. Very easy is for players with an Elo of around 1400 and usually involves finding forks and two move combinations. Normal is meant for players between 1700 and 1900, and very hard is for players from 1900 all the way up to GMs (or so it says). I chose the "very hard" mode with the engine playing fast.
I managed to win when Giraffe played rather poor positionally, but it also introduced some tricky tactics. To me, in the Sparring Mode it did play pretty human-like...no playing like a grandmaster, tossing a piece, and then going back to grandmaster-strength play as engines seem to do when they are dumbed down. Conclusion: it might make a good engine to practice against if you are an OTB player and need a partner.