We had a good discussion on the forum a short time ago about this very thing.
There are two modes - Constant Velocity - and Exact Stop.
Constant Velocity is adjustable, but basically the computer reads forward and computes the next move ( i.e. the next change of direction). As it slows down from the present one, it also accelerates into the next one. This obvious results in the "rounding" of corners.
There are parameters you can alter to make the corners more "square" but you need to experiment with the setting that suit you.
On Exact Stop the axis must do just that - come to an exact stop. The problem is, travelling at 150' per minute, it takes some time to slow down and stop exactly on the button - and then from stop, the carriage that has to accelerate back up to speed. If you have a lot of changes, this will appear to be very jerky, but something you will have to live with I'm afraid, if you want to travel at light speed.