I bought this to replace my plastic shaft which was useless with brushless power. This is a major improvement. Now there is no twisting, and no high speed chatter that the stock plastic exhibits. Acceleration is better, and braking is considerably better. So far it shows no signs of wear, so it's holding up well.
The quality of this is excellent. It is very nicely anodized, and genuine tamiya-like quality. My only complaint is it is slightly too long, so it ends up making the diffs bind because it pushes the bevel gear out. The easiest way to fix it was grind a bit of metal away from the shaft that the bevel gear sits on so really I extended the flat spot on the shaft. It is a 5 minute fix and now it's great. However, I shouldn't have to do that for something that is meant to fit.