The SSD is the faster of the two but, to my mind, it's real hard to justify buying any serious amount of storage with either. RAID just shows too little benefit in gaming, though it does get you to your desktop faster when booting. SSD has obvious benefits but ..... I can't forget how Intel just abandoned early adopters of the G1 series and just left em hanging. Trim is still a bit rough tho fixes are "promised".
My recommendation to my son was in building hsi rig was go w/ a single decent and quiet HD for now and grab an SSD in 6 months......by then, they should be faster, free of the bugs, new firmware, more competition and lower prices.