It is ideal for quickly viewing pin activity, debugging a few nets, creating simple prototype tests and doing some small flash programming jobs.  No learning curve, no fuss, no muss.  Up and running in minutes!

For bigger jobs where you want to do full board scans on static boards, script tests, apply test vectors, do high speed flash memory programming in production, etc., please check out the following links.  These vendors offer a wide variety of JTAG tools that can suit your every need.