Choosing between the two filters is a question of which filtration criteria you would like to prioritise. Both are suitable in the same range of waters.
PRECISION FILTER
The original Precision filter will allow for the most control and overall softening and will produce the best tasting coffee - especially for filter coffee. But note that this filter has a shorter life span.
ENDURANCE FILTER
The new Endurance filter will focus on alkalinity control (one of the most important factors in coffee) and will achieve a higher TDS (total dissolved solids) overall. The Endurance is much more durable lifespan and will result in more litres filtered. Note, a slightly higher TDS is often preferred for espresso.
In summary using the Precision filter is slightly more expensive per litre but it can offer superior control and taste.
The Endurance filter will come very close to the Precision in taste, but will last much longer.
For further question on the Peak Water Filter system please visit Peak Water's FAQ page