I haven't been before but I was seriously looking at going at one point.
When I was looking, I was only really interested in going through the official travel packages. My reasoning was:
1. I'm less likely to mess up the travel itinerary if my booking is through one provider who takes care of everything (travel, hotels, tickets).
2. My personal opinion is that my experience would be enhanced by being part of a larger group of Lions fans - along with the other experiences that I read up on (e.g. meeting players etc.)
3. My personal opinion is that, having never been to Australia at all, I wouldn't feel like I've missed something out due to the official tour not passing by. All I'd do is note it down for a future trip. I appreciate that this might be different for someone like yourself who has visited before and may have particular areas they want to visit whilst in the country.
4. I would have only been booking for 2, so it probably wouldn't have been as expensive (relatively) as someone booking for more than that. I imagine for a larger group there is more scope to saving money when booking your own tour.