Many people rush into RAID without understanding it's purpose, what it is, and what it is not. Only later do they find that performance isn't what they expected, or they loose data they thought was protected.
Each type of RAID has it's advantages and disadvantages.
RAID 0 is about performance. It works by increasing transfer rate which is useful when doing serial access of large files. But typical usage in Windows (or any modern OS) tends toward random access to relatively small blocks of data spread over multiple files. In this case the drive spends most of it's time moving the heads and platter position to the data in question and relatively little time with data transfer. RAID won't do much good for this situation. There are legitimate uses for RAID 0 but not many.
The purpose of RAID 1 and RAID 5 is to protect access to your data, but not the data itself. They are not the same thing.
RAID 1 and RAID 5 provide redundancy so that if one drive fails access to your data continues as if nothing happened. This is an enormous advantage in a busy server where downtime is very disruptive to business activities and a major cost. Drive replacement can be deferred to a more convenient time, and with hot swap can be done without downtime at all. The main problem with RAID 1 is that you need 2 drives to provide the storage capacity of 1 and the cost is often hard to justify for workstation use. RAID 5 provides better storage efficiency, but you need at least 3 drives.
But no form of RAID ever devised can protect your data. RAID (except RAID 0) will provide protection from drive failure only, and even that cannot be relied on. In the event of a serious malware infection, accidental or malicious file deletion, other hardware failures, etc., all data could be lost.
To protect your data you need backups. Files of any importance need at least one backup copy while those of particular importance need 2 or more backup copies. Backup copies do fail and this often happens when you need them the most.
