Hi,
I have been working with Jlink form the past three months. The community and the open sources available make it easy to work with it. So, I suggest you to use Jlink.
What does it mean "better"? What are the criteria? in every case IDAP-link expert @hnhoan is on the forum, all tutorials from his blog should be working and if you encounter any problem I encourage you to post comments on his blog rather then here...
@vam510411 I do agree that SEGGER J-Link is kind of standard, it is reliable, works with many tools and for Nordic chips you can get it as cheap as $40 on every nRF5x DK board but what do you mean by "open source"? All SEGGER firmwares and SW components are pretty much closed source as far as I know;)
The IDAP-Link is a CMSIS-DAP Jtag. You can use it with Keil, CrossWork, Arduino and many other IDE including OpenOCD & Eclipse. It also comes with a command line flashing program made for nRF5x series, the IDAPnRFProg. This utility can flash multiple boards in parallel. There multiple way to flash nRF5x with IDAP-Link.
Using IDE (Keil, Crossworks, OpenoCD, Arduino...) great for development and debugging.
Using IDAPnRFProg : flashing Softdevice + App + DFU without merghex + readback protection and parallel programming. This mode is the fastest.
Using SDCard also no merhex require. Copy SD.hex firmware.hex and dfu.hex onto a SDCard. Put in the IDAP-Link and press the program button.
