Londoner, the most useful responses to me were those that started with a personal message that addressed my questions, which showed me that the owner had actually read my inquiry. Some of those were fairly long and personalized, and I liked that.
Then, most of the longer responses went into detail on their booking procedures, as well as their apartments, the basics of things to do in the area, including links to Google Maps, etc. One of them started with an acknowledgment that it was pre-written information in the form of "here's some information I have put together that I send to people who are looking to stay in the area." That was absolutely fine with me.
I should say that most of these apartments didn't have their own websites, which is why all the information was in an e-mail. I did get one response that was a bulleted list of links to the owner's website, which had all the information from the other e-mails and more. I found that helpful, too, and like the longer replies it showed me that the owner had at some point taken the time to put together a lot of information in order to be helpful.
If most of your inquiries are from non-English speakers, I would think that long paragraphs might not help as much. Perhaps the list of links back to your website would give all the information without being overwhelming upon first read?
Then again, Gmail now has an auto-translate lab for messages, so if a non-English speaker is inquiring from a Gmail address, I'd say just use simple sentences and let the software do its best.