Yes much less expensive options exist.

http://www.synology.com/us/products/DS411slim/index.php

I don't know about this specific model, but I've already installed a few Synology NAS'es and up to this day they still perform flawlessly. When it comes to NAS'es I would only buy Synology or Qnap (or maybe Infrant/Netgear, but those are REALLY expensive). I don't think you can go wrong with either brand.

Another happy Synology user. I've got one box which ran non stop for two years, then sat in a parking lot in a shipping container for 18 months, and has subsequently run non stop for another 18 months.

I don't have any personal experience with Synology products, but it looks decent based on the specs sheet. Proper AFP and other file protocols (outside of SMB), lots of media features, drive expandability, and a decent admin interface.

I'm surprised there isn't a comparable ReadyNAS unit like this out yet. 2.5 inch form factor drives are becoming more and more commonplace for home storage, and do offer a noticeable power usage benefit compared to 3.5 inch drives.

The DS411 Slim is the upgrade to the currently available DS409 Slim.

http://www.synology.com/enu/products/DS409slim/index.php

Me too. I'm using a DS207+ which is running 24/7 for about four years now. Never had a problem so far.

-Peter

Another happy Synology user here too.

I have a DS101g+ which has run faultlessly for many years, and have now upgraded to a DS710+ as my primary NAS and am using the DS101g+ (hacked to a "DS107" and running an upgraded DS107 firmware - see the Synology forum for info) as a network backup for the DS710+.

I considered the DS409slim when I was researching NAS upgrades and was initially attracted by the low power consumption, low noise and small footprint. However, the limitation of only being able to use 2.5" drives put me off.

IMO, unless you really needed the space saving, you could get all the other benefits by running 2.5" drives in the other models that use a Freescale processor, and have the flexibility to use 3.5" drives if you needed more space for the price.

The 'full size' models give you the choice of 3.5" or 2.5" drives (the 2.5" drives bolt straight in without adapter cradles and plug straight into the same SATA connectors) and I can confirm that the 710+ runs cool and quiet using 2.5"drives, although its power consumption will still be higher than a 409slim due to the Atom mobo in the 710+.

Peter, good info. I hadn't twigged that other models were setup to accept 2.5" drives without problem.

Can drives be loaded as easily in the larger units? For some reason, I'm under the impression that larger models require more in the way disassembly.

All models require the drives to be screwed to a cradle as far as I am aware; some models eg. the 409slim have the cradles accessible via a simple catch and slide-in arrangement, some like the 710+ also have a catch and slide-in arrangement and are hot-swappable, others (mainly the single bay units) require minor disassembly of the casing with a screwdriver, while others such as the 4-bay 411+ need a panel removed by thumb screws, so quite a variety but none of them very difficult.

Unless you needed the hot-swap ability or are changing drives frequently, I would not say that it would be a major consideration.

Based on this thread, I pulled the trigger on a DS211. So it's all your fault (all of you) if I don't like it It looks pretty good so far, though.