I shoot a PM8 myself and i personally feel they shoot nicer than the DM6, 7 and for the money better than the DM8 aswell. I 'downgraded' from a Geo and i prefer my m8.
If you fancy going older and don't mind the weight / bulkiness i also agree with Sid. The DM5 is the softest shooting marker i've ever shot
Not shot one myself but apparently the DM9's are supposed to be insane if you've got the money