Updated 11/7/2011: Added USB 3.0 info
Updated 9/29/2011: Corrections in Synology information
Browse through the SNB NAS, QNAP and Synology Forums and you'll find many, many posts asking for help in deciding between two similar models from these two popular NAS vendors. You can dig through specs, research forums and user reviews until your eyes bleed and post dozens of "which should I buy" queries around the net. In the end, the final choice has to be yours.
In an effort to either make the choice easier, or maybe harder for those ultra-analyticals among us, I asked each company to make its case for why you should buy from them instead of the other. Both responded, but with varying levels of detail. In some cases, I was asked to not quote responses directly, so I've paraphrased. Before we get into the responses, let's first look at some general information on the consumer NAS market.
The Big Picture
In general, consumers don't buy that many NASes. In-Stat's Worldwide Consumer Network-Attached Storage: Low Penetration, High Growth report (May 2011) [executive summary with specifics redacted] states "estimated household penetration of consumer NAS in North America will be 4.4% [emphasis mine] at year-end 2015[emphasis mine]".
Given the low average selling prices of consumer NASes, the report says that "worldwide revenues for consumer NAS were approximately $678.4 M [emphasis mine] in 2010". So compared to a total $5 billion external storage market in 1Q2010 (source IDC), consumer NAS is very small potatoes.
So it's understandable that NAS manufacturers are looking to small to medium businesses for real revenue growth. This is why you're seeing products like QNAP's recently-released Intel multicore-based eight and 12 bay 2U rackmount NASes, NETGEAR's ReadyNAS 3200 and 4200, Thecus' Core i3 based N8900 and Synology's RackStation and Deskstation.
For "big iron" enterprise-grade NASes, the IDC report linked above lists the top companies by revenue as EMC, IBM, NetApp, HP and Dell.
For consumer NAS, the In-Stat report linked above says Buffalo leads the consumer NAS market in terms of units shipped. But this Infonetics release from June 2011 says that NETGEAR led the worldwide NAS appliance market in 2009 "by a wide margin", but QNAP pulled even with NETGEAR in 2010. The release doesn't say what measure of market share was used, though.
A last look at market share is available in the In-Stat table shown below, which I found posted in this Origin Storage article, which probably came from the In-Stat's Worldwide Consumer Network-Attached Storage: Low Penetration, High Growth report.
It shows Buffalo #1 in terms of units shipped, with NETGEAR in fifth place, but with neither QNAP nor Thecus in the top 11. (Thecus is outlined from the Original Storage article, not from the In-Stat report).
So this would seem to contradict the claim that QNAP and NETGEAR are neck-and-neck in leading the consumer NAS market. It seems to be clear, however, that between QNAP and Synology, the latter has a smaller share of the market. Note that In-Stat's data shows Apple as #2 in NAS market share in terms of units sold, with only one product (the Time Capsule)!
Synology had this to say about its absence from market share reports:
We're not included in the In-Stat report because we don't report any type of numbers to analysts. Most of our competitors are public firms (or owned by conglomerates) and these numbers are public domain, we choose to keep our sales numbers close to the chest. We also turn down offers to OEM our products for larger companies, which leads to inflated numbers for those that do so.
Strengths and Focus
Both companies said they weren't interested in getting into detailed feature-by-feature comparisons. So if that's what you are looking for, you can bail out now. But they were happy to talk about their core strengths and company direction. This is more valuable than you may think, because it helps you understand each company's mindset.
In my former life as a test equipment engineer, the company I worked for set reliability as Job #1. This was drilled into my head from the day I joined the company until the marching orders changed years later, in response to a changing market. It formed many design decisions, which in turn set key aspects of products we designed. So understanding what a company values will help you understand the products it makes.
Synology said its primary focus is on improving the overall NAS user experience. This includes performance, features and support with equal importance on each. Support is done in-house by teams in Synology's US, Taiwan, UK, and Germany offices. All products have at least a 2 year warranty with 3 years for "+" series products.
Synology also believes it led the market with the first AJAX based DiskStation Manager admin GUI and that its "desktop" model will be adopted by other manufacturers.
Synology Disk Station Manager User Interface
I've included screenshots of each OS so you can judge for yourself.
QNAP V3 OS User Interface
For those looking for more quantitative differences, Synology noted that it is the only NAS manufacturer to offer expandable NASes that connect to expansion units via high-bandwidth dedicated interfaces.
QNAP's primary focus is clearly on business users with a specific focus on virtualization. It is definitely after a chunk of the business now enjoyed by much higher priced products from NetApp, HP and Dell and to some extent, Drobo. To support this focus, QNAP has more models with hot-swappable bays (even single-drive models), LCD status screens and USB 3.0 ports and supports 6 Gb/s SATA on some high-end models.
QNAP was more specific in its responses than Synology. It said it believes its iSCSI implementation is more stable and flexible with features such as multiple LUNs and targets, flexible LUN mapping and LUN masking. QNAP's iSCSI implementation includes iSCSI initiator ("VDD") support that enables SAN-like capability. It also pointed to its Real Time Remote Replication (RTRR) feature (" 7-10x faster than rsync") as a key advantage for enhanced security through faster and more frequent backups.