Are high sensitivity hall effect switches just noisier versions...

[e100]

of normal hall effect switches. For example the Allegro a3144 switches at about 300 gauss whereas the high sensitivity version from the same manufacturer switches at about 100 gauss.  Is it the same basic sensor but with a lower threshold?

Would there be any benefit to using an analogue hall sensor and setting my own thresholds, or is that just reinventing the wheel?
The application is for measuring the speed of a water wheel that rotates at about 2 Hz.

Mike