The standard articulated boom lift consists of a single jointed arm. The advantage of such an arm is twofold. First, a single joint articulated boom lift can reach twice as high as a normal boom lift, due to the fact that it can store double the length of arm on the same vehicle bed. The second feature, which makes it especially popular in crowded and difficult to reach settings, is that the second arm can be extended horizontally as well as vertically - meaning that the platform arm can be extended over large obstacles to reach even more hard-to-reach places than the average aerial lift.
Electrical boom lifts are more popular in indoor settings like warehouses and factory floors. Because they can be charged from a standard 110 volt socket, they are easy to use and cheap to run indoors. They can be driven at full elevation to allow for the inspection of crates on a second or third level inside a warehouse, and feature an articulated arm (though not quite as far-reaching or maneuverable as the standard model of articulation) for reaching a maximum of areas.
A mast style articulated boom lift is often the best choice for those truly tight spaces - warehouses with narrow aisles, or consumer store floors, for instance. A mast boom lift works on the principle of a primary telescoping mast for reaching heights. This mast can then be rotated at full extension to allow a full three hundred and sixty degree level of access for the second articulated arm, allowing operators to be lifted out of a cramped space - like an aisle - and then maneuver above the obstacles to more easily carry out their tasks.
Towable boom lifts are more versatile in outdoor conditions around San Francisco, especially places where it may be difficult or impossible to drive the small-chassis standard aerial lifts. Built on a trailer with an extendable support base, these types of lifts can be towed behind a pickup or other towing vehicle to a work site in San Francisco and then locked down for operation. At that point, the towable boom lift operates exactly like a standard articulated boom lift. This kind of lift is the perfect solution for places like construction sites in San Francisco, where the ground you have to work on may be nothing more than dirt or mud.
Scissor lifts in San Francisco are especially useful in the sort of situation where you don't have the room it takes to extend the long arm or arms of a boom lift or articulated boom lift. A scissor lift works conveniently enough on the same principle of a pair of scissors - a structure of crossing, interlocking parts contracts to extend a platform straight up. The upside of a scissor lift is that it never takes more horizontal space than the base. The base can also be lighter than that of a boom lift, since it's center of gravity is directly over the base and it doesn't have to compensate for the lever action of a boom lift.
The downside to using a scissor lift is that because of the more complex structure required, they are often not able to reach as high as the simpler boom lift designs. That's not to say they can't reach many high places, however. Some scissor lifts can reach as high as forty or fifty feet, which is plenty for most situations.
With a scissor lift, the platform can never go anywhere but directly over it's base. This can be better for some situations and worse for others. If you need to get up and into something around San Francisco, like a tree for trimming or a power line for repair work, for instance, a boom lift is probably going to be your best option. If, on the other hand, you need to ascend a vertical surface like the side of a San Francisco building for paint work or external surface maintenance, a scissor lift will probably be the better option. It all depends on exactly what you're looking for in a particular job.