Sorry for this superlate answer but this thread must have gone missing.
I personally prefer the Western Beach. Why? First of all it is very quiet. Because it takes you about usually a bit more than 45 minutes (we have done it in my mates Wrangler in 25 mins) from east to the westside as it's a long and dragging inland offroad track. Count in another 90 to 120 minutes to get up to the inland track entry from the barge. I guess what I try to say is, you won't see many people there. Second, it's a lot less windy and the ocean is ocean on this side is normally very calm and good to swim in (not sure about the sharks but we had an incident with a big fu**ing turtle).
Along the western beach runs a creek that comes from the inland. It is very refreshing and has clean water with tea-tree oil in it. So you won't even need a shower as it's a good freshwater source running directly behind the main dunes where we used to camp on.
What to avoid?
Leaving you food outside over night. Because there will be packs of dingos everywhere. And they will rape your camp site if you leave your stuff outside.
Bringing an AWD. Don't try to discover Fraser Island with an SUV such as a Toyota RAV4, Honda CRV, Subaru Forester, Nissan Xtrail or a Range Rover Freelander. They will get you stuck in the deep sand which could await you everywhere, not just on the beach at high-tide. They simply lack the clearance and can become quickly a pain in the ass.
Being a road warrior. Drink Driving, doing Donuts on the beach, drive your beloved 4WD into Eli Creek and get it bogged there (that really happened) ... avoid all that. There are police and rangers everywhere, the fines are heavy and in the end nobody wants Fraser Island to be locked up because of bad publicity.
2x D-Shackles, 20m Snatch Strap, Gloves, UHF Radio, a shovel, probably Maxtraxx or some sort of planks that can give you traction when you got stuck and be all by yourself in the sand.