My view on the subject..
The Samsung F4 2TB 5400rpm and WD EARS 3-platter ~5400rpm would also be able to beat the older velociraptor in sequential I/O; the F4 is capable of up to 140MB/s sequential reads. Being 5400rpm disks they approach the sequential performance of the newest 7200rpm and even 10.000rpm disks, because they have the highest data density of all. 7200rpm disks are still limited to 500GB platters while the F4 and newer EARS would use 666GB platters, leading to higher sequential throughput.
The higher rpm disks would still win from any 5400rpm disk regarding random IOps; though for that task any HDD sucks and an SSD would be the most logical choice; for example as system disk.
While i agree with MRFS, that RAID0 doesn't increase the chance of disk failure, is does increase the chance of failure of your storage, due to problems with the RAID engine itself. RAID engines kicking non-TLER disks out of the array on every bad sector causing the disks to perform recovery more than 10 seconds, is a prime example. So the disks don't die earlier, but non-RAIDed storage versus RAIDed storage has the advantage of not introducing another layer to your storage setup which can fail in itself; RAID is a single point of failure, just like your filesystem.
So using any RAID may increase the chance of at least the RAID layer failing or giving you trouble; RAID can improve reliability but can also decrease it; common onboard-RAID drivers available on Windows and virtually all Hardware RAID controllers would have problems with disks performing deep recovery. These kind of RAID implementations are less secure than modern software RAID under non-Windows OS (ZFS, MD-raid in Linux, geom raid in BSD).
Whatever you do, never trust your important data to just one thing. Have it backed up, and double backups for your most important data. If you do that, you can focus on performance and use RAID0 and don't have to be scared about failures, assuming it's no problem to restore from backup and have a bit of downtime.
Cheers
-sub