I've used openfiler in the past (also on a test network). Whether it's suitable for a corporate environment i'm not sure...Cant comment on those products, but I've had good success with OpenFiler on test networks. The price is right too (free!), although you can pay for support if you need it
Personally, I'd put OpenFiler with a support contract (1000eur/year) on a par with SanMelody etc in suitability terms. Its got a lot of nice enterprise features and its nice and simple.
What are you looking at spending and have you already got the hardware?