I find the rear rack very useful, because I do like to hang my (big) backpack from the saddle's rails and have it rest on the rack. Also I like the little wheels on the rack - they make it convenient to roll the bike when folded.

That said, the front luggage system is really very good. I found the bags too expensive, but the front carrier block and the stand-alone frame are cheap enough - I modified a shoulder bag I already had to hang it from the carrier frame. Works great.

I guess it depends on how much luggage you'll generally carry. I like the flexibility of the rack *plus* the front luggage frame.