I never really thought about Mariska but I think I actually like it. It's much better then Marissa. I'm sick of that name and all various spellings of it.
I prefer the sound of Marissa / Marisa, but Mariska has more spunk. Either one is nice. The only problem is that Marissa / Marisa was overused when Melissa was at its prime. Marissa is dropping in popularity now though.