Hi Ozy, I've never heard of the no limit company but thre are quite a few campervan rental companies about, new ones springing up all the time.
The main issues you face are that to get a decent size one, you're probably looking at $200+ to $300+/day depending on season.
There are far cheaper ones about, right down to about $50/d or less but very basic and not much more than a mattress in a mini cargo van.
Now to buy one, again it'll depend on the size and what you expect to pay, usually the bigger the more expensive and the more limited market to sell back in to.
And for a relatively short time, the selling issue is quite a gamble irrespective of size though there'll perhaps always be some adventurous backpackers on the lookout for something cheap but they know it'll usually be a buyers market.
Added to selling complications in Australia, you have registration/vehicle inspection requirements that vary from state to state and for instance if you buy a campervan on the east coast and want to sell it in a different state, you have a problem.
Time of year, weather and where is also a big factor in comfort of a van for at height of summer, they can be real hot houses and in the north, very humid hot houses, not too comfortable and if it's raining and you're kind of couped up in this mini living space, not too enjoyable.
In winter, they can become a bit like a refrigerator, especially at night, even in months near winter in the south, so one way or another it can mean a bit of roughing it.
No reselling problems and in some relocations you'll even see there is a fuel allowance.
There is limited time for relocating between cities but look at earliest PU and latest Delivery dates and it is often greater than time allowed and in those cases you can book an extra few days, usually up to 3 @ a discount rate.
I actually bought a car from No Limit Campers. It is quite a young company and I found them to be very helpful. In general, I agree with what was said above regarding the slight uncomfort in dealing with cars in Oz. However, there are some ways to make this experience more relaxed and enjoyable.
I bought a Land Crusier (troopy) from the No Limit company. The car had a great set-up of a camper (bed and all) with the terrific advantage of 4x4! which, in my opinion, is a must in Australia. I ended up circumnavigating the continent, and loved every minute of it. (I also kinda got attached to my car). Anyway, the advantage of No Limit is that they take a lot of the unwanted anxiety away. They give you one night accomodation for free, to get your things sorted as you land in that area. Furthemore, they commit rebuying your car at the end of your trip. Just the idea of knowing you have a safety net is a great advantage. (I was lucky and sold my troopy to a local farmer, who payed me more than I initially paid for it). The selling of the car is not so bad, as everybody think it is.
Anyway, thought you might find this information useful. Have a wonderful time in this incredible land and don't forget to take a lot of water.