Pros: Good number of ports, two internal two external. Great for home use, casual stuff, maybe HTPC. The idea of this card is great... just not the execution.

Cons: All features except RAID5 available for 1/5 the price on any other card of this type. The ONLY benefit of this is the RAID5, and with two internal and two external ports, unless you have an internal port multiplier (in which case, what is going on with your motherboard???) you will be using the RAID5 on an external rack, enclosure, case, etc. And this DOES NOT work. Whenever anything on the eSATA ports is disconnected, instead of hot-plugging (hot-unplugging?) properly, the drive(s) are marked as disabled. This will put your arrays into degraded (and eventually, failed) status and will compromise functionality. This will happen whenever drives are unplugged, powered-down, or maybe even spun down by the enclosure. This will also happen whenever the PC is put to sleep. The real fail here is tech support. After dozens of messages (many incomprehensible pseudo-English) and days gone by, I give up. The tech support people have no idea what they are talking about, repeatedly ask questions they've already got answers to, and do NOTHING to help -- all they are paid to do is insist it's somebody else's hardware is "incompatible" (as if a WD 2TB drive or a standard port multiplier is where they get to pass the buck, when it's obvious their hardware is the misbehaving component). Shamefully bad customer service. I am ETERNALLY grateful I let my external enclosure do its own RAID5 instead of having a disastrous experiment letting this card run the RAID5 on those disks. It would have worked wonders until the first time, I'd pile on all my data, I'd put the PC to sleep, and then it would have been a catastrophe.

Overall Review: Buy something else. If you want RAID5, get a different eSATA card that costs more and might be more fancy than you want. If you just want a few extra ports for RAID0, RAID1, JBOD, whatever, then get something cheaper and simpler. Also, beware updating the drivers or "webgui" for this device. If you've disabled the incredibly loud horrible beep (which you will encounter if you are using the eSATA ports!!) it will be enabled again after any updates or changes to the drivers/gui. Since I do all of my hobbying and home tech stuff late at night, that is a problem for me to be sure.

Pros: Faster than it's little brother, the 622. Paired it with an existing Sans Digital 8-Bay esata Tower Storage Enclosure TR8M+B. It supports esata port multipliers out of the box, and after driver installation, it found my existing RAID and took over the duties of the smaller 622 card quite handily. Highpoint's software might be clunky, but it is consistent, and it autodetected my existing raid just fine, and carried over all my settings when installed on the same box that had had the lesser 622. No hand-wringing over adding drives back in to a RAID or loosing any data over it.

Cons: Failed after 2 months. Good thing I kept the 622 laying around. The 644 Just went dead. My raid failed to come back online after a reboot, so I swapped back in the highpoint 622 that came with the raid tower, and the raid came right back up immediately. Tried switching it back to the 644 to see if it was just a fluke, and no dice. Tried re-seating the card, no dice. It's toasted. We will see if the manufacturer does right and replaces it. Until then, 1 star. As an aside, if you find yourself ever-hungry for a do-it -yourself RAID solution with good performance in a small-to-medium business setting, go with an LSI megaraid card. They run hot and are expensive, but it offers a true hardware raid solution as opposed to these highpoint "my-first-raid" cards that offload calculations onto the CPU. I bought an LSI, and after getting it to run in ubuntu, never looked back. Still want to get my tower raid 8-bay working well, though so I will continue to look for a compelling esata card that support port multipliers (or an LSI megaraid that supports port multiplier of sata)

Overall Review: Good product, when it works, cost effective raid solution, would be great for a home or small business.

Pros: When functioning well, this unit seems to have good throughput, and the eSATA ports properly handle port multiplication.

Cons: One port hooked up to an external enclosure is working fine, all drive operating normally. One port hooked up to another enclosure has drives randomly oscillating between FAILED and OK. The disks are new, and each is set up as a single disk JBOD (closest thing to pass-through I could find) The RocketRAID is being used solely as a port multiplier and disk controller, its RAID functionality is not being used at all. The negative on this review is also largely based upon Highpoint support. The only support option I can see from their website is the online support. It seems that the only way to use their online forums is to register a device with the serial number, the device being inside a server box and running in production. My only option then is to bring the server and all it's VMs down just to get a serial number. Also, it would be nice to have a support telephone number listed on their website.

Pros: nothing

Cons: intermittent reliability, crashes, silly technical support from manufacturer.

Overall Review: this was a huge mistake and waste of $100.

Pros: I purchased this controller to connect a Icydock 4-disk external enclosure via eSATA to a Ubuntu-based KVM host. The RocketRAID 642L is an actual RAID controller rather than a 'fakeraid' adapter like you see on most of the Sil-based adapters. It took some effort to get it working, but it was worth it. HighPoint's tech support is fantastic. They were extremely responsive and were able to provide updated driver source-code as well as suggestions to resolve my issue. Great guys for sure.

Cons: Tricky to get working on Linux. If you're not comfortable building kernel modules from source, and spending some time troubleshooting and tweaking things, this card may not be your best choice. Nothing wrong with the card itself; every system is different, so you need to be aware that other devices in your system or even BIOS settings may prevent the driver from working properly.

Overall Review: I have this on a Ubuntu 12.04.2LTS server running as a KVM host. Config is as follows: - Gigabyte GA-970A-UD3 motherboard - AMD FX(tm)-8120 Zambezi - 32GB RAM - 2x 320GB SATA disks for OS - 4x 1TB disks in RAID-5 on IcyDock enclosure - 6x 256GB ISCI volumes on QNAP server Some things to note regarding Ubuntu & KVM on AMD-based boards using Realtek network chipsets: - Upgrade your motherboard's BIOS to latest stable - You need to enable IOMMU in the BIOS - Add the following parameters to grub for your kernel: "iommu=pt iommu=1" You'll have a lot less trouble with your network interfaces. Trust me.

Pros: From my experience theses card are solid and work great. I see a lot of negative reviews and I guess I'm glad I have not had to deal tech support to this point in time. I have an older model of this card that is 9 years old that I keep around as a backup in case of failure.

Cons: The gui is clunky but fine

Overall Review: As there is not a lot of information about the Negative reviews (system config) there are other factors that can contribute to the success or failure of any external raid enclosure. I can tell you I use an enclosure that requires a port multiplier for Raid 5 and the enclosure its self is not capable of doing any kind of disk management. My old config had 5 disks WD Blacks 4 disks were in Raid 5 with 1 disk as hot spare. My new config is same 5 disks 1 as a hot spare the disks are WD gold datacenter drives they make up about a 20 TB video streaming array and pushed out over 4 million hours of playback time this summer. My guess is that if you have an enclosure that is not also running a raid and you pay up for a better drives the card may work better. Like I said Im not picking fight just want to give my experience I have been using some flavor of this model for 9 years and 5 different servers and they have all worked great for me.