High Point Technologies have nice cards to, they are axtremely fast and reliable.
Depends on what you need.
For now, the RocketRAID 2640x4 is the only SAS/SATA II controller they build. It doesn't compare directly with the ARC-1680, ARC-1222, or CalDigit RAID card.
No built in cache
No battery option
No RAID level 50, 6, 60
No EFI support (Only BIOS support listed on website)
No external ports (future expansion/ increase RAID array)
For me, these are needed.
From what I could tell on other models, they tend to also lack cache and battery specs as well, at a minimum.
Again, the listed differences may or may not mean anything, depending on what someone needs. Or expect to need in the near future.
Hope this helps.