Pocket springs are individually wrapped coil systems that are stitched into mattresses below a comfort layer of foam or other material. Unlike traditional innerspring systems that are interconnected, pocket springs are entirely independent allowing for added contour and pressure point relief than older innerspring models.
A mattress crammed with inferior springs will not be better than one with fewer, more quality springs. Look at the range of specifications including the materials used to top and fill the mattress – this is what is important is defining the quality (and price) of pocket spring mattresses.
https://www.dandsmattress.com/product-category/mattress/pocket-coil/
Pros: Because the springs move independently they offer more support for your body, and are ideal for people of two different weights as pocket-sprung mattresses reduce that ‘roll-together’ feeling. Durable materials and superior comfort to traditional innerspring systems.
Cons: Sleepers should be equally as interested in the foam that is wrapped around the coil system – if that is low quality, the bed still may be uncomfortable. Can be heavy to turn, due to the density of their fillings. If you suffer from allergies, be sure to check the fillings carefully, as many use natural materials like lambswool, which can aggravate allergies.