I've been to one many years ago. I was new in Japan and didn't have any friends except for some virtual penpals who never wanted to meet up so I thought why not I have nothing to lose, but like the poster above says it's pretty much the same as konkatsu parties. Immediately too serious chicks. Talking about marriage and baby. The whole experience felt like a job interview. I would not recommend it, but if you're introverted or have difficulties making friends then sure you can give it a go. I'm still in touch with a girl I met there so there's that.