If your building has more than G + 2 floors you will probably want to consider an electric traction elevator. Traction elevators are better suited for taller buildings, since they are capable of much greater speeds and heights. Traction elevators are available in a variety of drives such as thyristor controlled drives and variable voltage, variable frequency AC (V3F) drives which offer significant power savings, smooth ride and accurate leveling.
Hydraulic elevators are used frequently and have a vast range of applications. Small buildings under G + 3 floors are typically where hydraulic units are found. Hydraulic units are limited by the number of floors that they can serve. Often these limitations are not due to the inability of the equipment, but reflect more on the cost of installation versus the long-term maintenance costs. Hydraulic elevators, which serve many floors in high traffic facilities, are not as cost efficient as are traction units, in regard to the units' performance and maintenance cost.