I've got one and I love it. I bought it to bring down the cost of practicing with a double action gun before I started reloading.
If you shoot a regular double action auto, you'll find it to be very helpful, but be advised there is no de-cocker. the safety makes it cocked and locked.
Mine improved my shooting 100% during my second year of shooting. THOUSANDS of rounds through that little guy and ZERO malfunctions with high velocity ammo except for dud .22s.
You'll need to use high velocity ammo, but that makes for more realistic practice anyway. Feel free to contact me off list if you like, I've also got two 87 target models that are very cool...