In the past, I always got better bang for the buck by going with smaller hard drives in a RAID 0 setup. Now that SSD's essentially have onboard raid 0 and you see better performance from larger drives, is this still true? Are these new drives anywhere near SATA III bandwidth limits?
msot SSDs are near sata III max speeds. you will find a better buck now for getting a single larger SSD rather than smaller ones. you will find more performance from 2 smaller drives but that just doubles the possiblities of failure. plus you dont see a noticeable jump in performance in day to day operations
One thing I've read to be cautious of when putting SSDs in a RAID is that many separate RAID controllers (on motherboard or expansion card) don't support TRIM (though by now there are probably some that do, and I would guess that the built-in RAID controllers for larger SSDs do). As far as SATA III bandwidth limits, there are some PCI Express SSDs that have much higher bandwidth (and of course much higher cost), but apparently have issues with motherboard compatibility and can be difficult to use as boot drives.
you will find more performance from 2 smaller drives but that just doubles the possiblities of failure.
I'm not so sure it really doubles the possibilities of failure, especially if the OP is correct about large SSDs having internal raid 0. If that's the case, an external raid 0 might only require replacing one of the smaller drives, instead of buying a new larger drive. By the time the smaller drive model becomes unavailable, one can hope there will be a faster large drive for less than one of the smaller drives costs now.
However, if you're looking for the fastest boot time possible, RAID will actually slow that down, because it waits for several seconds to let you press a key to enter the RAID config menu.