Pros: It comes with a low profile bracket.

Cons: None that I can see.

Other Thoughts: I installed this card in an HP Pro Liant DL385 G7 server for the purpose of doing backups over eSATA to an IcyDock MB559U3S-1SB external enclosure. Windows Server 2008 R2 installed drivers without needing to insert the enclosed disc. There were no conflicts between this card and the already installed Smart Array P410i RAID card.

Pros: No fuss 2 eSATA port pci express card using 1 lane
Works with Sans Digital 4 Bay eSATA Port Multiplier JBOD Tower Storage Enclosure (no eSATA Card bundle) TR4M+BNC and 4 2TB drives (2 Seagate, 2 Toshiba)
Works under latest ubuntu server (12.10, 64-bit) with sata_sil driver after disabling drive write cache (WCE=0)

Cons: Only running drives in SATA2 mode, not SATA3. During card bios boot it shows drives running at SATA2 level even though the card and drives support SATA III

Had to upgrade Ubuntu server to the latest to get the drives to quick throwing SATA errors. Required disabled drive write cache to keep the array error free.

Other Thoughts: This isn't a Sil312X cihpset, rather an Asmedia 1061; which is supported under linux, it certainly isn't error free. In fact, I ordered a second esata controller just in case this one continued to have trouble. It's been stable copying close to 100MB/s for the past 24 hours as I mirror over 5.2TB of data. I ended up doing the following to get things stablized.

1) upgraded to 12.10 64-bit (3.5.0-19-generic)
2) used hdparm to disable the write-cache on each drive (hdparm -W 0 /dev/sdX)
3) reboot the host to allow scsi layer to recognize drives have WCE=0

After this, I've had zero drive stalls (iostat shows drive at 100% utilization but with no read/write activity) and no other errors showing in dmesg.

Pros: Works fine with individual drives and installation was painless (Dell Optiplex 790 w/ Win7-64)

Cons: Doesn't work properly with my Addonics port multiplier (based on a Jmicron chip). The system would freeze randomly with the multiplier connected and on the occasions where it wouldn't freeze, data transfer was very slow. Wasted a ton of time in troubleshooting.

Other Thoughts: Give this one a pass if you're considering using a port multiplier. Not sure if fault lies with this card or the Asmedia 1061 chip it's based on. I've since replaced it with an eSATA card that uses a Silicon Image 3132 chip and the setup works fine.

Pros: - Solid eSATA option with port multiplier
- Does not impact boot times like RAID cards

Cons: - SIIG website is not updating their drivers in timely manner
- price (I believe there are several other cards with the same AsMedia hardware for a cheaper price -- at the time of purchase I did not realize the hardware was same)

Other Thoughts: I purchased this eSATA card because Intel has not implemented driver support for port multiplier (the hardware is there) in their 6-series boards. I backup my WHS 2011 server to an external eSATA enclosure once per week, then I turn the enclosure off and store it in a separate building.

Before installing this card I was using a HighPoint RR622 raid card. It worked but it caused significant delays in booting the computer, and management of hot-plug (safely remove hardware) was cumbersome.

I installed the drivers from the SIIG site (1.2.6) and there was a problem when unplugging my eSATA enclosure. After safely removing each drive after backup, then turning off the enclosure itself, the drivers did not recognize the drives as being disconnected (still showed as ready for removal in Device Manager). Downloaded drivers from station-drivers.com (1.3.4) and they corrected this problem. SIIG should update their drivers more often.