Hey marco, I just switched at the beginning of this month to AH from Mweb - well I can say that it's been mostly a great experience. I am on the 1Mbps R297 p/m bundle. I've had mostly free reign this month both with realtime and non-realtime services running at great speeds. However in the last part of the month there has been some shaping on NRT services - it was around for the past week but this weekend it's been pretty good.
As for usage, well its the 29th and I've done about 120gb this month - I run torrents probably around 2/3rds of the day with it being off probably between 12pm and 6-8pm while I work. I'm still using online streaming and youtube from time to time during my work hours. So yeah I think there is a possibility to hit between 140 and 180 but I'd reckon 115-130gb is a fair consistent expectation on the 1Mbps package. 2Mbps is probably the way to go if you can spare the cash to guarantee 180gb upwards over the month - the business uncapped with probably be absolutely worth it as AH reckons theres no shaping at all..