Summary: One of the things not listed on the specs is that the raid is an SIIG, which if I would have known I would have not gotten it. I've been burned by SIIG every time I've used one of their products....this is no exception.
Pros: The unit looks nice, and the initial setup was pretty easy. I put 5x3TB drives in it as a raid six. Set up an ftp so I could access it remotely and in the first year I would have given it five eggs over two.
Cons: Several weeks ago I had the raid say a drive was bad. No big deal, I took the spare and put it in it's place and let it start rebuilding. After about halfway through the building of the replacement drive the unit locked up and dropped 2 more drives out of the raid. I managed to get one to be recognized and worked hard to get all the things not backed up off of it. Then after reading an post on the forums I updated the firmware and it picked up the other drive that had...
Summary: Really enjoying this machine. Looking forward to years of service from it.
Pros: Fast, easy to setup. $150 discount was awesome.
Cons: A little limited in terms of expandability in terms of modules. This is supposed to be addressed by the new OS6 soon to come out. Had to do a hard poweroff and it took 2 days to rebuild the volumes - 5 x 3 TB drives. Probably on par with other systems tho.
Pros: Fast set up with (4) WD 3GB Red drives. Once I installed an Intel 1GB NIC, speeds were 100MByte/sec read & write. Using it for backup with my Acronis True Image 2013. Took a little fussing to have that see the Thecus by UNC but got it working without having to load any other software.
Summary: The have zero problem so far with the N5550. It's been running 24/7 since it was purchased during the boxing week with 4 Seagate Constellation in a RAID 5 array. Read / write throughput have been excellent between 80-110 MB/s. This is super fast compared to my 4 year old but reliable ReadyNAS NV+ ~ 20-25 MB/s. The ReadyNAS is now a backup for the N5550. Overall I am very happy with my purchase from a price / performance perspective.
Pros: Build quality, speed, price/value/performace ratio especially when it's at a discounted price below $450
Cons: Documentation could be better but not a big deal if you have some knowledge of networking e.g. WAN/LAN, link aggregation, iSCSI, etc.