Just to jump in again: We are in southern Mexico where we have 30 Amp service at best. Temperatures are in the low to mid 30s C (85F to 95F) with high humidity. (66% and up) We have set the temp to 79F and are able to maintain that all day using only one compressor. Compressor start up current draw will cause a voltage drop low enough for the Xantrex to drop AC to the rig if the second compressor should kick in. With better shore power voltage regulation I'm sure that we could make it cold enough to break out the parkas.
Noisy under the bed? Yes. I've no experience with roof A/Cs but if it's too hot we couldn't sleep anyway. Temps here are usually in the mid 70s over night so after about now (7:30 PM) we'll switch to the exhaust fans for the night.