Linux software RAID
Mylex DAC960 RAID
Intel gdth RAID
They all suck in different ways:
Adaptec corrupted data left and right. We replaced them all. MegaRAID has shitty, closed, unuseable tools and shitty /proc interfaces. Intel gdth is good with nice /proc interfaces, but some tools aren't so quick returning. None of them have anything near a consistent interface. IBM ServRAID seems great, but I think the control binary is closed? Maybe it's not anymore, with IBM being all pro-Linux. That was years ago. Still my favorite RAID array.
I really can't recommend any one of them. No, DAC960 is definitely the best.... no question. But they were bought and that line discontinued. :-(