My humble conclusion: Clearly there is a broad consensus favoring a/c in the trailer.
By my count the plusses start with a/c being absolutely critical for comfort in the hot-hot weather, (no surprise there, considering the number of senior citizens here - you paid your dues, you're untitled to total comfort in your golden years), and, the plusses end with a/c being a key to resale value (no surprise there, considering the obvious wisdom of all (most).
In practical terms nobody seems concerned or bothered much by the noise a/c produces and I chalk that up to "...it really ain't that bad considering the alternative." (See 2nd sentence, paragraph 1.) Also, it probably ain't that bad. Clearly, a night of white noise trumps a night of sweltering. Thinking most don't run air all night anyway, but use it before bedtime to cool off the interior and bring it down to a tolerable sleeping temperature. (That might not work in the Texas hill country.)
Either most of you choose campsites with electricity, or carry a generator, (sorry, solar guys) so the power issue is irrelevant.
For you who camp mostly in northern temperate zones Kar-nack senses a grudgingly reluctant sub-conscious admission that it probably is better to have and nMexico, d than to need and not have. That's OK, no justifications necessary. I think that way myself, but-- I do draw the line at hanging a $99dollar unit out my bathroom window. (Don't have one anyway.)
All these observations make perfect sense to me, and, so... I... am... gonna be getting an air conditioner.