As an advocate of the Astra Superior Platinum blade, I have to say that I find the 3rd shave of a blade the smoothest of all. That is not to say that the other shaves are not smooth, it is just for me, the third shave is the most effortless.
That said, there are some razors in my little stash which can feel a little harsh with a brand new Astra, then calm down on subsequent shaves - but that is the razor gap and my technique - not the blade.
If you are wondering on how many shaves the blade is good for? For me, a daily shaver averaging 1.5 passes a day, I can get 4-5 days. Beyond that is false economy when you are risking nicks 'n' weepers just for the sake of pennies :|