The conclusion is somewhat contradictory....
"Cost is based on two batteries and is in Australian Dollars. $/Hr
rating can improve if batteries are purchased in bulk packs. Note that
the Digitor batteries were purchased from Dick Smith Electronics in a
40 piece bulk pack, whereas most of the other batteries are purchased
on two or four battery packs, whichever was the minimum available.
Pricing is therefore not fairly compared for the Digitor batteries,
but regardless of this their performance figures are very good."
According to the current DSE catalogue, the 40 pack, S4040 @ $25.98,
are DSE brand, whereas Digitor are only available in four packs, S3094
@ $1.98 -- which works out at $19.80 for 40.
I'm still none the wiser as to which ones I should be buying!