Some people say it doesn't matter, some do. When I bought my XDm 3.8 I didn't even know the term. In the past year I've gone from an SR9, to a CZ75b, XDm 3.8 9mm, and now an M&P9. Out of the 4 the XDm is easily the hardest to shoot "fast". It's accurate sure.. Probably equal to the CZ and M&P. But once you start double-tapping the XDm starts to fall behind. I would say that's it's only downfall.. Everything else about it is amazing... Especially the trigger. Yes, after enough practice, you can learn to "control" the muzzle flip on the XD... But it dawned on me after shooting the M&P that I was working really hard to keep tight groups while shooting fast with the XDm. So yes, the XDm has a high bore-axis and yes that means it's going to be harder to shoot "fast". If you're not concerned about speed, (read competition) then it probably isn't an issue.