Just got back last night from the Dropbear Adventures tour booked through Flashpackers Hervey Bay and I can't understand why anyone would book with any other company. Mark is the BEST guide you could ask for, and after seeing some of the other tour groups while we were on Fraser Island, we were even more happy with our decision to book with them.
The package offered by Flashpackers (you can book it at Hervey Bay or Noosa), was absolutely perfect for us. There are no other tours that will let you do a night (or however many you want) in Hervey Bay and then actually get dropped off for the night after the tour (or vice versa) in Noosa, so not only did we save time and money by not having to book a bus to/from or leave an unused car rental while we were on the island, but we got to stay in two amazing accomodations on either end and also get from A to B with seeing everything in the middle.
Our group was particularly lucky since the weather was not supposed to be very good and many people had cancelled their tours, so we ended up with just 5 people and Mark as the guide all in one vehicle. This allowed us to see almost everything on the island (including Lake Allom, Basin Lake, the west side of the island... and some more spots that the majority of tour operators don't go to). The big buses would not have even been able to make it over to the west side of the island, and it takes a lot of time to get from one point to another, so we were just cruising along since Mark is a very skilled 4x4 driver and we didn't even have to wait for the others in our "tag along" tour to catch up since we were all in one car. We all got the opportunity to drive it ourselves as well, but there were some pretty tricky spots since there had been a lot of rain, so I was very glad to have someone like Mark behind the wheel.
We ended up staying at Base Hostel (Hannah who runs it is also awesome and we were grateful that Mark organized this for us since it was really rainy at night and camping would have been no fun). It was really nice that he made this call with lots of time to spare - some of the other camping groups were out the first night we were there and all ran straight to Base for their second night when the rain had just been too much.
The sights were of course amazing as you will know by reading any review of Fraser Island (especially when no one is around and you have Lake Wabby all to yourselves!), but Mark, Dropbear Adventures, and also Flashpackers for their perfect nice rooms on either end of the trip, are what made this top the list of things we've done here in Australia. Could not ask for a better guide, better food (we ate like kings!), or a more comfortable way to get around the island (soooo glad we did not book one of the big bus tours once we actually saw them - people were in and out so quick and did not seem to get any time to actually appreciate the sights, plus wayyy too many people all in one spot).
The whole experience felt more like we were hanging out for a few days on the island with a friend that had been there and knew all the ins and outs than being on a tour - so glad we got the chance to do this and can't recommend Dropbear enough!