I have been a Superhost for 5 years now, but I used to agonize over leaving negative reviews. In the beginning, I was leaving too many 5-star reviews because I hadn’t gained confidence as a host yet. Now I’m just as honest as possible, without thinking about their review of me.
Also, I only let 5-star guests instant book with me now —(everyone else has to make a request and wait for my approval), so I usually have pretty great guests. Guests who are trying to maintain their 5-star rating are usually good. I have had a few problems over the years with people new to Airbnb, and sometimes even with guests that have a couple/few good reviews. If guests are rude, ask for discounts or extra service, and make hosting more difficult, they don’t deserve a 5-star review . The guest won’t like the review, but they will definitely improve their behavior next time. They know the hosts they’re trying to book with may have seen their negative review—so they work overtime to be polite (& they want to get their ratings back up).
I would avoid saying “high maintenance”, and avoid getting into too much detail—the lower stars say a lot (and they can’t see the stars unless they’re looking hard to find them). In the public review, I try to start off with something positive, then I state briefly what made hiring them difficult. It’s best to be honest—it will benefit everyone in the long run. Most importantly, it will help them be better guests in the future.