I also have a 4 5/8" BH 9mm/357 and until recently my experience had mirrored Dodge's. I finally noticed that while I have no problem with the base-pin jumping in .357, the 9mm makes it jump loose within one cylinderful, which makes accuracy go all to heck. I didn't notice this until recently, as it wouldn't pop all the way out. A Belt Mountain locking base pin fixed this.
I also looked for ammo the gun liked, and finally I did find some. Oddly enough, for my gun the el cheapo 115gr FMJ Blazer ammo did the trick, combined with a new base pin.
There is also an expectation factor to consider. I expect a blackhawk in 357, 41, 44 or 45 to be capable of cutting a cloverleaf at 20-25 yards. But I realized I don't have this expectation for my 9mm semi-autos, none of which are tricked out target models. When I pulled the range back to 10-12 yards and shot the 9mm BH side-by-side with the semi-autos, it equaled or beat them easily with just about any ammo (after I installed a locking base pin). I'm not sure quite what this means, but it did change my opinion of the gun.
So while I have posted negative reviews of the 9mm BH in the past, I have changed my mind. It is a fun gun to shoot and now I am more likely to take it to the range with the 9mm cylinder and leave the .357 cylinder at home.