I sort of developed a heuristics for how I do Couchsurfing. I started with 0 reputation last year and it's been very positive for me.
Basically you look for people that have logged on within the last week and have close to 100% positive review. Also there should be at least 3-5 reviews from SURFERS that stayed with them (meaning they host well not just surf well), and better if they are given those reviews in the past month or so (so they are still actively hosting). And TBH it's often the 1 or 2 negative reviews that are the most revealing about the host so if you find someone close to 100% be sure to read those. Sometime people just don't jive well with each other and this help you see whether the one off experience was due to the host's bad nature or the surfer's. Sometime I find someone with 1 or 2 negative reviews and they are plainly due to the surfer's assholery, AND the host is able to explain it well, that comes off as a huge plus in my book in evaluating the host because you can see how they react and reflect on bad experiences.
This works well in larger cities because you have plenty of hosts to sort through. In less populated place you have to loosen up these criteria and take what you can get. To be honest when I started I just randomly chose people simply because they accepted surfers at the time. And still I lucked out and didn't have any bad experiences. Side story: one time I surfed with a guy sharing a place with his mom and lived way off in the suburbs about 30 minutes from town, WHILE they were redoing their entire house so their entire basement was filled with exposed wires. But overall he was nice enough and pointed me to the bus stop (1.5 hour ride to where I wanted to walk around) and at the end of the day brought me to a meetup and later to a bar.
So obviously I am biased but I have a lot of faith in the system. In the end of the day if you do your research and choose your host with some care, you should be fine. Just avoid people that comes off as creeps based on your intuition and there shouldn't be a problem.
I am a guy by the way, for girls I'd suggest being much more rigorous with this method. Most female surfers I've talked to share similar methods and reported few problems.