We owned a Trak Shak (for five years) before buying our current Goldstream Crown. No kids though.
As others have said, think carefully about what you want to do and where you want to go. We took the Trak Shak up to the Cape (but not along the OTL), it did the Gibb River Road, the Tanami etc etc without any problems. I would take the Goldstream (it's an off-road version) along most of these roads/tracks, but I would be very aware of the Goldstream's greater weight and size.
It used to take us about half an hour to set up the TS - it only takes 5-10 minutes for the Crown, probably slightly more for a Storm. The TS has a lot, and I do mean a lot, of canvas which was a real pain if it was wet. Unless you're slightly larger, ie stronger, than average you may have troubles setting up and pulling down the TS by yourself - both of us had to do it. The TS has much more room inside (if you put the moveable kitchen outside), but you need a large level campsite for it, much, much less for a Goldstream, and sometimes this was a real problem for us.
And if you're buying a second-hand TS, check to see if it was built in Australia or China. The quality of the earlier Chinese-built ones was somewhat suspect.
