Pros: I bought the 4i version of this card just 2 years ago and I needed to expand my array to over 4 drives and this was the best option I could find, it works just as reliably as its little brother. I have SATA II drives in the array now, but this card will last me for years to come since its SATA III capable. I also have the BBU unit (MegaRAID LSIiBBU07) so disk writes are blazing fast, beats any on-board controller RAID solutions I've used by miles.

Cons: Expensive for a personal build, but the speed and future proofing is hard to beat!

Pros: + Good performance
+ LSI and 3Ware are respected names.
+ Price from Newegg was much lower than the competition.

Cons: - Picky about motherboards. Was not even detected in a Supermicro PDSME+ motherboard, even though many other PCIe cards worked well in the same slot. If your motherboard is not actually right their on the compatibility list, do not buy this card.

- The cables included with the kit are useless unless you have a 3Ware RAID enclosure. For normal setups, such as using a standard Hot Swap case from, say, SuperMicro, you need to buy the fanout cables (additional $20 each [4 drives each] as of this writing). In those cases, get the bare card. Note that fanouyt cables used in some older LSI cards are not compatible with this one (look closely at the connectors).

- Gets extremely hot, even idle. You will definitely want a significant amount of air flowing across the heat sink.

Other Thoughts: The BBU (Battery Backup Unit, search for LSIiBBU07 ) is required to safely use high performance mode, which aggressively caches disk writes for speed.
The cost of the BBU as of this writing is insane for a small battery and control circuit, and you have to replace the entire unit when the battery wears out.

Pros: Easy to use, very versatile.

I bought it, and installed it, with the BBU (Newegg: 16-118-118, called a LSI00161).

Started with 2x160 mirror + 4x1TB Seagate 7200s RAID 5. Added two more Seagate 1TBs, migrated from RAID 5 to RAID 6. Wasn't quick, but it let me do it live. Went into Linux, unmounted the array, pvextend, lvextend, extended the file system, and I have an extra TB on a volume full of data without having to reformat to get that extra space. Love it!

Cons: Slow builds/migrates.

Other Thoughts: I like the 3DM2 web based interface. Pretty useful. Tech support was fast and friendly when I applied a kernel update without pre-building the drivers into my initrd. Oops.

Pros: fast, works well, good company

Cons: Only comes with Two Mini-SAS to x4 SAS cables (CBL-SFF8087-06M)
Usually need 3ware SFF-8087 to Multi-lane SATA Forward Break-out Cable - CBL-SFF8087OCF-06M (2) unless you have a 3ware backplane.

Other Thoughts: Used a lot of different 3ware raid cards, all good.

Pros: I'm using it with 8x Hitachi HD32000 2TB drives in RAID 6 (12TB array). Individually the drives give me 110MB/s writes and 90MB/s reads. The array gives me 275MB/s writes and 700MB/s reads. My read speed is completely saturated given the 90MB/s per drive. This is a major step up from previous 3ware cards, I have 3 different systems running the 9650-8LPML with 8x SATA-II drives in RAID 6 (just like this machine), yet those ones consistently give 200-250MB/s reads.

Cons: The 275MB/s write is kind of low, given an 8 drive array with 110MB/s write per drive. I have a BBU and the cache mode is set to performance, I've performed all of the tweaks suggested by 3ware/LSI, yet this is where it's saturating. Still better than my 3 other 9650 8 drive raids, they typically give write speeds of ~200MB/s.

Other Thoughts: If you're running Linux, make sure you do the tweaks suggested by 3ware, they will significantly improve your speeds. The ones I am using are (my raid is /dev/sdb):

echo 64 > /sys/block/sdb/queue/max_sectors_kb
echo 512 > /sys/block/sdb/queue/nr_requests
echo deadline > /sys/block/sdb/queue/scheduler
echo 20 > /proc/sys/vm/dirty_background_ratio
echo 60 > /proc/sys/vm/dirty_ratio
blockdev --setra 16384 /dev/sdb