There are 3 versions of Type A cubes currently being sold:
Type A cubes can make good speedcubes and remain widely used by speedcubers. This is arguably the best type of 3x3 without lube, and feels very creamy and smooth. However, after lubing, its speed falls short of other cubes. Overall, it's still capable of reaching sub-10 second times.
Type A II cubes have "tracks" on the sides of each edge which supposedly help prevent popping. Unfortunately, this can cause the cube to lock up more.
New Type A cubes have little tabs that can be inserted into the bottom of each edge. This is another experiment in popping prevention.
