Hi Mate
I have no specific advice about the type of challenge camper you are after. All I can offer is that if the camper you are looking at is supplied by challenge campers in Rydalmere NSW, which is the same company that supplies (The now Chinese) Track Shaks and Campo-matics, steer well clear and go to another manufacturer.
The company is run by a people who wont tell you the truth, have major supply issues, after sales service is hopeless and I wouldn't recommend them to anyone. Also what you see on their show/display models is not what you get delivered.
I bought a brand new Track Shak from them Last year. It was so bad that they took it back and paid me my money back to go away. It is a shame because they have some of the best designs on the market, but the company appears hell bent on substituting quality parts for cheap crap to increase their profit margins.
Go with another brand that has a solid reputation (not living off one developed by others previously) for quality and after sales service. Also when you need spares you will have to wait for them to come in from China.
Regards
Jas