Shawn Hammer wrote:
Not having raised floor doesn't matter so long as cooling is delivered properly to the racks (top down, in row, or in rack),
Why do you believe that it is proper to deliver the cooling "top down"? Heat rises! The cool air needs to be delivered to the bottom (raised floor) or front (alternate row cooling) so that it flows over/thru the computers on its way to the hot air intakes which should be located above the back of the cabinet (above the "hot row") or top of the room (for raised floors).
Disadvantages of no raised floor: IMHO the cooling is not as efficiently delivered or managed. Since electrical costs (and by extension, cooling costs) is one of the biggest costs for data centers, this cost is a large part of what you pay. If they aren't being efficient in the design, their costs are higher, and you end up paying higher fees. Yes, the build-out costs are higher, but it's the ongoing hosting costs that go ever higher year after year that will rack up your bill.
Advantages of no raised floor: Someone can't sneak (a person or data line) into your cabinet or cage thru the floor. Racks are more stable in the event of an earthquake. Overhead cabling is easier to follow, maintain, repair.
jc