Both are great. I would pick the one that is most affordable and obtainable to you. Have you considered developing your own codes to simulate the gratings? Take a look at the videos under Topic 7 at the following link. Everything you need to develop your own codes are there.
Thanks Dr Raymond Rumpf for your suggestion. I understand the coding is the most appropriate solution for Grating design, but to explore many complicated gratings and to design with its associated devices, the software may be useful.
An alternative is GDS from Sol Photonics. It is specifically meant for various Fiber Bragg Gratings (uniform, chirped, different apodization profiles, etc).
There is a free evaluation version you can play with (limited functionality).