Thanks for your comment...
J-Link (IAR) supports all ARM devices but cannot be used with Keil tools.
J-Link (Atmel) supports only Atmel ARM devices but can be used with all tools.
J-Link (Segger) supports all ARM devices and can be used with all tools.
for comparison of models.
Now, I understand that the Atmel J-link is not for general use for newbie like me. Any recommendation for ARM development board? NXP or Atmel?