Re: £490 will get you a WD 16TB raid 0 drive from Amazon. (2x8TB Reds)
"RAID0 can be more reliable than RAID5" is an example of very dubious arguments. The basic points are:
In RAID-0 any drive error is losing you data, and typically a lost HDD means you have to wipe and restore the whole file system. Only upside is you *know* you are vulnerable so probable (I hope?) have a backup and restore plan that is regularly tested.
In RAID-5 you can tolerate one disk fault, be it a whole disk or reported bad sectors. Down side is folk over-estimate the independence of errors and the correct reporting of errors. If using any RAID system you really must do regular disk scrubs to make sure that the inevitable rebuild has a sporting chance of completing OK and not throwing up other errors.
However, if your data really matters than (a) you have a backup anyway, as RAID != Backup, and (b) you should be using something with double parity, at a minimum RAID-6 or better still ZFS RAID-Z2 since it has better write performance (more so with a SSD for the intent log) and additional checksums on the blocks so it can spot HDD lying or disk controller faults, etc. I think btrfs is planned to have a similar scheme (i.e. redundancy and extra checksums like ZFS) and some variants of GPFS (or whatever IBM call it now) has it, but on the payment of lots of extra money.