A cyberdeck is more then just a comlink – think of it like this comlink = smartphone where as cyberdeck = tablet-supercomputer
How this works in the game
First off you get the +2 superior equipment bonus because they are so good
and more over a cyberdeck is a nexus per the rules in Unwired and SR4
The rules below are those from Unwired p50.
Nexi: Nexi are high-performance “mainframes” able to run a larger number of programs than
standard nodes. They are commonly used by Matrix cafés, civic wireless access points, corporate servers, businesses that need VR workspaces and security nodes (see Slaving, p. 59), data havens, and for other processor-heavy tasks. The servers that run nexi come in a wide range
of sizes and processor power, from units the size of a modern-day tablet to a full-blown server tower. The more processor power needed, the more powerful and thus bigger the hardware of the nexus will be. In game terms, nexi work exactly like standard nodes with a few exceptions. They have a higher processor limit, allowing for more active programs (with the exception of agents, IC, AIs, sprites, and e-ghosts, which are limited by Response per standard rules—see
Response, p. 212, SR4). Their configuration and design also means that System rating is not capped by Response. Nexi are designed to run multiple personas; their persona limit equals System x 3. Nexi have a minimum processor limit of 10 and a maximum of 50.
They have 6 up-grade slots for modifications (per SR4 Book Arsenal p126) .
An example from Unwired of what is essentially a cyberdeck.
Evo Mobile Terminus: The Terminus is intended to provide a field nexus in situations where one is needed in an emergency: conflict-zones, disaster areas, media spectacles, etc. The Terminus
is commonly found in mobile command posts and media vans.