Most people don't have an issue, but the Australian government, for some unknown magical reason, took forever to process my application, and I was forced to fly to Australia before it was approved because medicine was commencing. By law, if you apply for a visa while offshore, you still have to be offshore at the time of its approval. So because I had already arrived in Australia, it was rejected, and I had to go through the whole process over again, including paying double and redoing all of the medicals. This second time around was an onshore visa.
But I have two friends who had been in a similar situation as I, and they flew to New Zealand for a week to be "offshore" during the approval process. This in turn had cost them less than applying for a new visa.
I had applied for my original visa probably about 3 months beforehand as well. I would say 95+% of people don't have an issue though.