I'm partial to Fiji Rock, so I think it just comes down to your personal tastes.
The only biological advantage I could see would be that it is a really porous rock. An aquascaping advantage would be that it interlocks and stacks nicely without the use of epoxies, zip-ties, etc. And Fiji Rock tends to have natural holes/caves for critters to make houses out of.
For me personally, it simply comes down to the look. It's a solid looking rock with lots of Swiss cheese holes, and the purple that usually comes with it is just a bonus, IMO. :bigeyes: