As long as you have good quality live rock, silica sand will become populated with worms etc. and function just like a sandbed of aragonite.
Aragonite sands' use as a buffer is overstated, and is redundant if you have live-rock or dose with liquid buffers like Kalk (or run an efficient Ca reactor).
Silica sand does not leach anything into the water and does not promote the growth of cyano or any type of algae. Those are just old wives' tales, I've never seen any solid science to back it up.
The only drawback to silica sand as far as I know is the color,, even the white-ish stuff is not as white as aragonite.
I think the most important thing is to ensure the sand is populated with the 'bugs' that one gets with good quality Live Rock,,,, without that fauna, you can get serious 'clumping' problems.