Works Great
I scheduled uTorrent between midnight and 8:00am to go crazy, and got about 1.3 gigs (w00t!). Available cap not reduced by any significant amount (I might have gotten started a bit early...). If my dodgy maths is correct, that works out to a decent ~50 Kbytes/s average. Under normal daytime conditions I get 10 KBytes/s max on BT, and average 30-40 Kbytes/s for HTTP downloads.
I guess either the throttling is loosened up a bit during this time, or network load was just less than when I'm awake. As pointed out in previous posts, let's see how it goes as more people start using this great facility. On the other side of the fence, this must be an interesting traffic engineering opportunity for iBurst - with public visibility, it would be embarassing if it failed miserably. If the network can't carry the load, it must be bolstered up to be able to do so.
If it works out, iBurst is once again starting to move into an area where they are an acceptable alternative to aDSL - I still shudder at the thought of paying the Telkom tax. I haven't tried any of the recently announced uncapped 384 Kbit/s offerings - will be interesting to see how the results compare...