I've seen both of these used to end processes. It is to my understanding that tskill is the older taskkill being that it's documentation is located in Microsoft Windows's XP Documentation while the newer taskkill is capable of closing several programs at a time according to Microsoft Technet Taskkill's Documentation. What are the advantages or disadvantages of using either?
TSKILL really has no advantages, to my knowledge other than being what some people learned first.
Taskkill on the other hand does everything tskill does, but more, with better documentation and more flexibility. It also allows wildcards, easy remote killing `taskkill /s serverName /IM "firefox"' and allows you to control exit forcefulness (Force kill, or allow graceful exit).