I have used it for a flat tire and have had mates use it as well. It is Australia wide the only stipulation they have is they will only take it to the nearest HD dealer and i believe that there is a KM limit on this also so if you are stuck in the middle of nowhere it may cost you per KM if you are over the amount stated in the policy. As for fixing stuff on the side of the road i doubt they would be able to do to much as all the guys i know that have used it have said it was just a flat bed that showed up to pick up the bike.
I used to be with NRMA (in NSW) and if i was doing a lot of interstate riding i would go back to them because you can select the type of policy and coverage you want as in they will ship your bike back to your city, rent you transport to get home or pay accommodation if needed.
I am with RAA and took out mid cover. Much better than Harley Assist, especially if out bush. Only issue I have is that RAC canceleld a callout because they had no vehicle in area to assist. Called RAA and they organised, but I had to pay and now will submit to RAA to see what I can get back. Whilst Harley Assist will get your bike to nearest dealer, RAA etc will get your bike home, assuming you have appropriate cover. My bike broke down in Bendigo last week with wires in a loom broken. Was going to get a local Harley mechanic to fix but RAA are now going to transport back to Adelaide so I will fix myself. Save me a heap of money that way.