You might get arguments about cock on opening being smoother or better, but I do have a word of caution about that conversion. If you look at the P-14/M1917 bolt, you will see that the cocking cam has a step. The cocking piece is actually partially withdrawn on opening to retract the firing pin from the primer, and it sits in that step until the bolt is closed. But this is only about 1/3 of the way to the full cock position.
The conversion kit makes use of that step by using it as the only cocking point. The bolt then cocks on opening, but only part way. Since the firing pin fall is only 1/3 of what it would normally be, the conversion unit uses a heavy spring and a light firing pin to get enough momentum to fire the primer, but it is right on the edge, and they have been known to give misfires.
What all this amounts to is that the conversion may not be reliable, especially under adverse conditions (dirt, dust, cold, hard primers). If something "wants to eat me", I want a rifle that can be depended on to go bang, no matter how it cocks.
Jim