I got a pair of the 1's recently so now I have B-I's, II's, III's, and IV's in rotation. I also have a pair of Yonex 305's. I have had no problems with the 1's in terms of my 53 y/o joints. They fit true to size but only if you wear thin socks. If you wear Thorlos, you might want to go a 1/2 size higher. In terms of cushioning, the order for me (from most cush to least) is: 4, 3, 1, 305, 2.
Redondo MP / BB 11 / Yonex RDS 001 MP