I really like my perpetual motion. It is definitely a medium / dryer lane ball. The cover is pretty strong but the core is mild. It gets down the lane easily and isn't too jumpy at the break point. This ball covers boards but does it in a controlled way. There are a few more reviews of this ball on the MoRich facebook site. The video on morichbowling.com is pretty useful. If you search a little bit, there's a good review on this site too.