I don't know anything about Coachmen or Forest River -- but after years of reading complaints about various trailers, I have concluded that every manufacturer makes misteaks, even the high-price companies. And only the unhappy people post -- we rarely see "gosh I like my trailer" threads. It is hard to say which company has the highest percentage of customer satisfaction. (Are there JD Power Awards for RVs, like there are for cars??)
You are absolutely right to look at the complaints as part of your decision-making process. But on the Internet, what you see depends on what you ask. So if you look for Coachmen horror stories, that is what you will find.
Hang in there!