Can XP RAID 5 last?

I know that software raid of any form is much maligned, but on the other hand you're on the hook for much more $$$ when hardware raid controllers fail, and not everyone's prepared to invest that much in enterprise level gear to protect what might be mostly entertainment media.

I've had a Synology CS-407, but it seems really underpowered, and uses Linux raid anyway rather than hardware, like many products of the same category and price range. Also twice in the last 4 months it has reported disk failures, when the disks tested just fine afterward standalone. Might very well be the operation-time-out-so-mark-as-bad issue. Back then the CS-407 plus 4x750G cost over $1000 to build.

So for a new raid box I decided to be adventurous and try the XP hack raid. Whole setup cost barely $600 with 4x1T drives and a bare bone system (E2200/4G RAM). OS is on a standalone drive, and it'll be used only as a headless file server with minimal interaction other than occasional reads/writes. No Windows update etc. So far I/O speed is far superior than the CS-407, though as Tom's indicates not as fast as hardware raid (nor do I need it to be).

Anyway, what I'm wondering is, do you think this setup is viable? Not viable as 100% loss-proof, but viable as in offers some degree of protection with ease of recovery. If OS fails, reinstall OS on the standalone drive and hopefully import the volume. If drive fails swap in new one...

I kinda wish raid never existed in a way, but we're not living in the days of small but reliable anymore. It's like having elective heart surgery.