We have implemented both practices in the Bay Area – it really comes down to a question of how the site is constructed and which municipality(ies) have jurisdiction over the site.
The seismic isolation platform work best when you are dealing with facilities without a raised floor, but we have used them in a raised floor environment in San Jose with pretty decent success. It just was a bit more involved.
The standard practice that we’ve been successful with across all of the various code enforcement people involves using 5/8″ threaded rod (or bolts) through the rack bottom into either anchors in the floor or Unistrut which has been mounted to the floor. We see this implementation in probably 90% of all facilities throughout the Bay Area. Let me know if you need particulars, and I can send you a PDF with the drawings of how we do it.