You gain the general use of a computer directly including a mouse, a larger screen, a hardwired network connection, etc. You also gain the power of Logger Pro, including video tools, gel analysis, and other features of Logger Pro, Logger Lite, or Graphical Analysis 4.
However, many people prefer to use a LabQuest without computers because LabQuest does not require virus protection or IT driven updates. LabQuest does not have a browser that would allow students to accessing inappropriate material on the device. LabQuests are designed for use in a laboratory setting. The units are splash resistant and shock resistant.
If your goal is to have a device whose primary purpose is data collection and analysis, a set of LabQuest devices can be more cost effective than purchasing an entire classroom set of computers.