I have set up and ridden a flhrpi with ABS, and I can tell you that it is a really good system. It will let the front tire howl with full braking but not lock up, (I tested it from 70mph). It was scary clamping both brakes full on to test the unit, and I made sure that I had on a full face helmet and full leathers before I tested it.
The down side is that it takes up over half, (the front half) of the right saddlebag. This unit is really big. In fact I have seen units on cars that are smaller.
I used to have a BMW F650 Dakar with ABS. The unit on the BMW was so small that it didn't change the look of the bike at all, and it was defeatable if you so desired.
I don't see why HD doesn't offer a BMW type system on all of its bikes. [smiley=nixweiss.gif]