One way to look at it is like this.
Let's say both implements are of equal weight, construction and do the same job equally as good and tilling blades wear at about the same rate etc...Given that the other aspects are equal (if indeed they are), then the only thing to consider is the drive. You can look at the drive train to see how wear affects the cost of future repairs or maintenance required in that area.
Use the initial cost of each and say a three or five year maintenance period...
They both transmit power but which one will wear faster? Which one will require more maintenance? Which one will cost more to replace components? Depending on the answer, you can determine how much of a value one is to the other. You may find out that a gear driven unit requires less expensive maintenance than a chain drive. That would make the KK a really good bargain...initially and even better over the years. On the other hand, if you find the Land Pride chain drive requires way less, then it's value would catch up after a given period of use, and then better over a longer period of time.
Obviously they don't last indefinitely, so you need to consider a realistic time line.