I've been hauling a drz400 for a couple of years now on a front hitch, and it works great with a couple of draw backs:
1. You CAN NOT haul at night. No exceptions. The bike blocks one headlight completely, and even though the other headlight is open, there is way too much reflection to see clearly.
2. The bike takes some abuse in the form of bugs, rock chips, etc...although the rock chips aren't too bad because I never tailgate, so it's mainly just bugs.
3. Don't get in an accident!
4. This is minor, but at freeway speeds my windshield washers spray "weird" with the bike on....something to do with airflow.
If you can live with these disadvantages, there are some good advatages too. You can always be sure your bike is hauling ok, it is easy to install the mount (about a 2 hour job, removing the bumper helps, and you need a big, tough drill), and my motorhome brakes MUCH better with the bike on the front than the back.
Oh, and you might think that the bike limits airflow for cooling, but last summer actually hauled at almost 100 degrees outside temp, with the cab air on and pulling a boat, and had no overheating of the engine or trans.