Answers are probably going to be a little biased, posting in the Yamaha forum.
That being said, I sold the stuff for years and have owned numerous pieces. Head to head with anything in their price range, they are hard, if not impossible to beat.
Currently have a CR-840 that sounds wonderful, stk modules or not. Also just got an A-500 for free, been 20 years since I've had one. The bench is full so it will need to wait it's turn.
They do tend to be valued rather low for what they are, other than the top xx20 models and the CR2040. That's fine with me.