Except you cannot purchase a drive empty, or with these newer drives.
All you can do is purchase is a configured drive, and if you wish to use those SSD devices, you would need to swap out the older drives and replace them with the newer drives.
Consider this, every year, newer devices are made available - sometimes even faster and less expensive.
You can wait forever to make a decision, as there will always be something newer just around the corner. Or you can make a purchase based on what you know and need today.
For example, Micron/Crucial have just announced the new C500 series that offers up to a 960GB capacity at around $600. A single drive with phenomenal capacity at an excellent price. On the other hand, it is a "version 1" with new controller, and new flash chips inside. See the Anandtech.com review published last week.