I really like have an AC. I don't have one in my home. It can easily reach 85-90 inside the house. But with fans going, it doesn't seem to bother me as long as humidity doesn't get bad, which happens during our thunderstorms.
In the trailer, 70-75 bothers me. I guess close quarters affects it more. Add humidity, and I'd rather go home than sit in the trailer. So I end up outside a lot. But if I need to be inside for any reason, I'd much prefer an AC.
Deal breaker? Not if the price is cheap enough that it would offset the cost of adding one.