As was stated, making the 39oz weight limit with the magazine is one of the challenges, but it can be done.
I shot mine in the 2008 Washington IDPA State Championships in SSP and had a great time shooting it.
There are SP-01s, older models with the 2 slots under the rail that will make weight and I did have a SP-01 Tactical that also made weight.
The double action first shot to single action subsequent shots didn't take much to get used to and since I was also shooting it in USPSA production division it was nice to be able to also shoot it in IDPA. I've also shot it ESP in matches both cocked and lock as well as hammer down start.
-Albert