We don't have AC, just the air exchanger, but it works pretty great. It has a cool heat capturing system built in, sort of this huge rotating honey comb structure that the air is pushed through, it collects the heat from the exiting air and warms up the incoming air. You do need to remember to change filters every now and then though. I was pretty disgusted when I did that the first time.
During the year and a half we've lived here, I've only wanted an AC for about 2 weeks. So I don't think we really need it. And a month of above 30C weather is not very common around here, it took the first two weeks for the house to warm up to uncomfortable levels.