From what I can see in the Vado 5.0 IGH picture, the stock suspension post travels along the seat-tube, which is at an angle. However, the saddle tends to travel vertically (not at an angle) when you are riding. This makes the seat-posts with the simple spring inside the seat-post ineffective. There has to be a mechanism to translate the vertical saddle/rider's movement to the action of the suspension to make a perfect suspension seat-post.
Cirrus Cycles Kinekt 2.1 and Redshift Shock Stop seat-posts each have such a mechanism.
- Kinekt is suspended on springs installed inside the parallelogram mechanism under the saddle. As you are riding, the mechanism translates the vertical movement of the saddle into the horizontal movements of the spring.
- Shock Stop has a parallelogram mechanism that translates the vertical saddle movement into the suspension spring(s) (one or two) working inside the seat-post.
Both solutions are equally effective.
There is a concept of "preload" for any good suspension system. A suspension seat-post must become preloaded so your own weight will not compress the suspension as you are getting on the bike. Kinekt has it done very simple way. After installing a colour-coded spring proper for your body weight range, you sit on the bike in your usual cycling clothes and shoes, and the other person helping you not to fall rotates the preload bolt at the back of the saddle until the bolt cannot be rotated any more. (There is a smart cam mechanism there that helps the thing be properly done). A scale on the cam makes it easy to memorize the proper position of the preload for a given rider.
Shock Stop has it differently. With the seat-post removed from the seat-tube, you just rotate a cartridge at the bottom of the post into a marked position according to the weight/preload table. You can also install an additional internal spring if you are very heavy.
As I said, both systems sport the same performance, that is, they cancel the road bumps totally. Kinekt is available in many seat-post diameters; Shock Stop is only 27.2 mm but you can buy shims for bigger seat-tube diameters.