There's some confusion here between folks who are addressing the issue of mounting panniers to front forks, a manifestly abominable idea, and others who are writing about the general concept of front panniers, which can be slung over your tank or (in my case) mounted to crash bars.
I like having front panniers, and I like it even more now that mine are hard shelled and lockable. This is not unsprung weight; it's weight mounted forward rather than behind me, and it's lower than the massive tankbags which I see lots of people using. However, I stow mostly lightweight stuff up front--tent, sleeping bag, certain clothes, bike cover, etc. Adding a lot of weight up there contributes to squirmy handling.