One key feature that is missing is the ability to place orders for fractional units. This is not important to all retailers, however markets selling commodities by mass or length generally take their orders by mass.
 
We have a clients that do this, some sell aggregates by the cubic yard & ton, others sell fabrics & findings by mass or yardage.
 
We can get the software to accept and compute fractions prices correctly, saves and recalls carts correctly however at checkout the quantities are changed to whole numbers.