ReadyNas Duo vs ReadyNasPro 2?

Pro 2 offers a much faster CPU, more RAM and much faster performance. Additionally, it has a number of business features that may be of interest including: active directory support, VLAN, ethernet teaming/bonding, snapshots, rsync-over-ssh, SNMP support and a longer warranty (5 yrs).

http://www.readynas.com/wp-content/uploads/2009/03/ReadyNAS_Comparison_Business.pdf

Here's an unofficial CPU comparison chart: http://home.bott.ca/webserver/?p=499

Here's something from another post of mine:

dbott67 wrote:

...although the Duo/NV+ is a great little unit (I bought one back in 2007), however, it is getting a little long in the tooth. The ReadyNAS developers have recently released an upgrade to the home-user market called the ReadyNAS Ultra in 2, 4 and 6-bay units [the Pro 2, 4 & 6 are designed for business users with additional features]. These units have a faster CPU and are more suitable for transcoding and media streaming functions going forward. The Duo & NV+ are quite capable at doing what it they were originally designed for (storing/sharing data and streaming media), but it's low-powered CPU is not suitable for doing some of the things that many folks who are into media are looking to do. All ReadyNAS products are based on Debian linux, however, support for the CPU included in the Duo & NV+ (it's a sparc-based CPU, as opposed to Intel Atom x86-based CPU in the newer Ultra/Pro series) has been removed in current generations of Debian development. This essentially is going to limit updates to the firmware. Development on the x86 line is much more active, and new features are being added regularly, both by the developers and the community-at-large.

The lack of development on the sparc platform means that newer hard drives that use GPT are not supported on the Duo/NV+ and therefore are already encountering a hardware limitation.