We recently upgraded the old evap on our house and added the 4 bedrooms as well. It suits us perfectly, and we find it really effective most of the time. Yep on humid days it isn't as effective, and on the 35/40+ days it will only go around 10 degrees cooler, but we can cope with that. I personally find it harder to cope with the heat if I'm spending all my inside time in cold refridgerated air con then the heat hitting you like a wall when you have to go in and out to work/shops/garden etc. With littles ones running around it's much easier leaving windows and doors open too.

We did buy a unit that is slightly bigger than what is needed for our house, and when installed they let us know which windows etc to leave open to make it operate the most effectively, and we really can't complain. But then I do seem to be one of the few that is okay with it!