Over the years I have used the 2, 3, 4 & 6. I really did like the 3 and initially didn’t like the 4. I had used the 3 on my “hot wheels” starting in 2009. I tried the 2 blade when I could no longer get 3s. I still use the 2 on my twin blade razor for my face whiskers. I’ve been using the original MOTO razor with the 4 blade for about a year. Tried the 6 on but for my head, the 4 does the best job!