If you really camp in 100+ degree temps then get the highest BTU available, but you'll probably find that it is noisier with a higher current draw, higher profile and cost as compared to a lower BTU unit. I now have the 9200 Polar Cub and it did perform well in high humidity / 100+ temps, but it will take longer to get the initial temperature down to 70s though. Took me about 45 minutes as I recall, where a 13.5 BTU probably would have done it in 30 minutes. Once at the desired temp, the 9200 cycles normally.
Most important to me now is lowest profile, lowest weight, quiet and works with the Honda 2000 generator. Good luck.
Present - 14' Ram 3500 4X4 DRW CTD AISIN 3.73
Past - 98' Ram 3500 4X4 DRW CTD / 99' LANCE 1110 / 04' ARCTIC FOX 990 / 05' ARCTIC FOX 990