The debate between air suspension versus coilover suspension has been a popular one for quite some time. Arguments for style, safety, utility, and practicality all flare up regularly, and bounce back and forth unsurprisingly.
AIR SUSPENSION
Function
Instead of the metal spring mechanism, strong rubber bags act as air containers. The bags are then connected to an air compressor and an air reservoir. The compressor does the job of inflating and deflating the bags, which is how the car gets raised and lowered. The resulting effects are a smoother ride and versatility in performance.
These systems come with a control unit that's located inside the car to give the driver complete control over the system. As this set-up is just a modification of a traditional system, changing how your car performs is just a matter of purchasing a kit. Air bag suspension kits can run anywhere from $400 to $1,000, depending on how sophisticated the set-up is. The more complex systems enable the driver to adjust for different road conditions or for city versus highway driving.
Within the last decade they've become popular within the custom automobile culture of street rods, trucks, cars and motorcycles. These systems are more complex and feature-rich, allowing for immediate adjustments to the level or height of the car. Known as "low riders," the suspension system is much more powerful using small electric or engine-driven air compressors. The control unit enables the driver to boost up any wheel of the car at any time to the point where the entire vehicle can be "rocked" at will. Typically, these cars are using a hydraulic suspension system wherein a bladder is filled with fluid by a compressor. This device is called an hydraulic actuator. The actuator is designed to brace the wheels against the ground so the force of the fluid into the bladder will lift the car.
The PROS
"Air ride" suspension, as it's sometimes called, offers several important benefits that may be useful to drivers interested in luxury cars. The primary benefit is ride quality: Vehicles with air suspension are often said to "glide" over bumps, while traditional steel spring suspension can cause a harsher ride. Also, air suspension is often adjustable. That means drivers can select a cushy ride if they're on a rough road or a harsh ride if they want to improve handling. Height adjustment! You can adjust the car's height with a push of a button !
You can understand more for air suspension from watching this video about the KING OF AIR suspension.
The CONS
While air suspension may be tempting, there are two downsides, both relating to cost. One is the cost of buying it in the first place. This is a very expensive option and can cost you more than 3000$.Buying it from the factory costs even more : The Chevrolet Tahoe, for instance, offers it, but you have to upgrade to the luxury-trimmed LTZ model to get it. That means spending more than $55,000 -- $15,000 more than the Tahoe's base price.
The biggerst drawback of the feature is maintenance costs. While air suspension is great when it works, it can be expensive to fix. And it's not a feature you can simply forget about: If it breaks, the car can tilt to one side while moving. That said, many drivers replace broken systems with more traditional steel springs -- a cheaper fix, but one that removes an important feature from the vehicle.
sources:
http://oppositelock.kinja.com/air-suspension-vs-coilovers-1462964641
http://www.stanceworks.com/2013/11/air-lift-performance-air-vs-coilovers/
http://www.reddit.com/r/cars/comments/2wycih/pros_and_cons_of_getting_coilovers_over_standard/
http://forums.vwvortex.com/showthread.php?4443963-PRO-and-CONS-of-Coilovers-VS-SPRINGS-and-Struts
http://www.automotiveforums.com/t492427-some_pros_and_cons_on_coilovers.html
http://www.ehow.com/how-does_5010001_how-air-bag-suspension-works.html
https://en.wikipedia.org/wiki/Coilover
http://www.superstreetonline.com/how-to/chassis-suspension/sstp-1303-how-a-coilover-works/
http://www.audizine.com/forum/showthread.php/187898-Coilovers-vs-Springs-Pros-and-Cons
https://en.wikipedia.org/wiki/Air_suspension
http://www.autotrader.com/research/article/car-tips/212905/pros-and-cons-of-air-suspension.jsp
