Enterprise hardware lies about fsync, because even if you loose power, there is a little battery on the RAID controller that's enough to flush the cache to disk or to keep it for hours until the machine is powered up again. When the battery goes bad, the write cache is disabled automatically.
On bigger hardware, like SAN storage arrays, the (redundant) batteries keep the whole thing running for a while after the loss of power.
You could consider that the whole battery backup etc. means that it isn't lying about fsync. It says that it's been permanently written, and then it makes sure that is has. It might not have been burnt to spinning metal, but the system as a whole will ensure that it's permanent.
"enterprise" disk is just that; it's just disk. I've not seen a disk with an onboard battery. You can put a raid controller in front of your disks, with or without battery backed cache. (most raid cards have an optional battery module.) But, even many gold plated 'corporate' systems I've seen omit the battery, as it's usually not cheap.
My personal opinion is that raid controllers are of little value without battery backed cache.
I just use MD in front of 'enterprise sata' drives, as without doubling my total cost for storage, I can't get a raid card, as far as I can tell, which is better than MD, and really, if I was to double my storage cost, simply buying twice as many spindles would get me better bang for my buck, I think, than a hardware raid card that cost that much.
On bigger hardware, like SAN storage arrays, the (redundant) batteries keep the whole thing running for a while after the loss of power.