I've been struggling with this question for the past 2 weeks. Here's what I've done so far (Mac Pro 2.8GHz 8-core, OS 10.5.6):
1. Purchased and tested RocketRAID 2314.
2. Purchased and tested DAT Optic PCIe x8 eSATA card. Based on Silicon Image 3124A chipset and available from OWC (macsales.com).
(Read/Write performance below measured by AJA Kona System Test utility.)
I am using 2 Icy Dock 4-bay Port-Multiplier enclosures and a Buffalo Tech 8x Blu Ray burner (model 816SU2).
Icy Dock 1: 4 Seagate 1.5 TB 7200.11 drives in RAID-5.
Icy Dock 2: 1 Seagate 750 GB drive in Pass-Thru.
RocketRAID:
1. RAID-0 performance with Icy Dock 1: About 180 MB/s both Read and Write.
2. RAID-5 performance with Icy Dock 1: About 160 MB/s both Read and Write.
3. Pass Thru performance with Icy Dock 2: About 60-70 MB/s Read and Write.
4. Blu Ray Drive: This card does not mount other types of eSATA peripherals. Only hard drives can be mounted. This was confirmed by a Tech Support engineer at Highpoint.
5. Uses a Web-Based GUI that is quite usable. Shows build progress for RAID-5 arrays; performs S.M.A.R.T. monitoring of drives and shows status; spins down drives after a specified period of inactivity; provides online capacity expansion for RAID arrays; etc.
DAT Optic:
1. RAID-0 performance with Icy Dock 1: About 180 MB/s both Read and Write.
2. RAID-5 performance with Icy Dock 1: About 50 MB/s Read and 10 MB/s Write. Yes, you read that correctly. Absolutely horrid performance in RAID-5.
3. Pass Thru performance with Icy Dock 2: About 60-70 MB/s Read and Write.
4. Blu Ray Drive: No problems mounting other eSATA peripherals such as Blu Ray drives.
5. Uses a JAVA-based RAID Manager GUI from Silicon Image. Does not show build progress of RAID-5 arrays; not does show or pass S.M.A.R.T. data; probably lets the O/S spin down drives (didn't verify it); no online capacity expansion.
Conclusions:
1. RocketRAID provides excellent RAID-5 performance. This is actually a key metric for me. The DAT Optic card was hugely disappointing in this regard. I wonder if any other eSATA card based on Silicon Image 3124a and/or 3132 will exhibit such terrible performance in RAID-5.
2. RocketRAID does not let me connect my Blu Ray drive. DAT Optic is more flexible in this regard. In fact, Silicon Image advertises compatibility with a wide variety of eSATA peripherals.
3. RocketRAID has a much more capable GUI.
4. During a RAID-5 build, both cards let you format and mount the drive in Degraded or Reduced mode. However, when I tried to format the drive with the DAT Optic, the Mac encountered a kernel panic. This happened repeatedly. However, once the array was built, the system was perfectly stable.
If you don't plan to use RAID-5, the DAT Optic card is the better choice because of compatibility with more than just hard drives. But if RAID-5 is important to you, the DAT Optic (and I suspect most other cards based on Sil3124) is a non-starter.
Finally, I called G-Technology yesterday to inquire about their standalone 4-port eSATA card (US $329). It's based on the RocketRAID 2314 so I wondered if they have modified the drivers for compatibility with optical drives. According to the fellow in Tech Support, it will in fact mount optical drives. If anyone is using this card, I would really appreciate if you can verify this.
P.S. When I tried to mount a drive with 1 NTFS partition and 1 HFS partition, both cards misbehaved badly with kernel panics, faulty drive messages, sudden reboots, etc.