It's clear that automated pipetting is faster than doing it manually, but how common is it for a lab to have an automated pipetting system, and what usually are the circumstances that a lab have before they purchase such a system?
The circumstances in a lab that would make automated liquid handling appropriate would be a need to prepare large numbers of samples by a routine method, so that it becomes more cost and time effective to install and program a machine to do the job than to do it with handheld equipment.
This is clearly the case in high throughput drug discovery work and also in analytical labs that perform identical tests on large numbers of samples; it's less common outside these fields although high throughput techniques can also be used in the development and testing of formulations, for example for personal care products or paints and coatings.
Standard automated liquid handlers are designed to deal with volumes in the microlitre to millilitre range and liquids that are not too volatile or viscous. Requirements outside this range, or extra constraints such as moisture or air sensitive reagents, will demand more complex and expensive equipment which may make automation less viable, although companies such as Zinsser and Chemspeed make devices for handling a wide range of liquid and solid substances.
To get a more specific answer than this you're probably going to have to narrow your question down to the particular industry and type of lab you're thinking of. If you're on LinkedIn you might get some useful responses from the Laboratory Robotics Interest Group discussion board.
Speed isn't everything. Reproducibility might be much more important!
Imagine that you have to transfer different volumes from five different stock solutions to a 1536 well plate and adjust the total volume by adding water or the common solvent of your choice. A programmable pipetting automat might be a blessing here.