The RND2000-100 is the original sparc based Duo now generally referred to as the Duo (v1) although that is not the official designation. It is powered by the old Infrant SPARC developed CPU and has been discontinued although many may still be in the retail chain. It is a good functional basic NAS, but is limited to 2TB disks (larger than 2TB require GPT (GUID Partition Table) rather than MBR (Master Boot Redord) and the no longer supported Linux kernel in use in the SPARC will not do that.
The Duo v2 (official name) is the RND2000-200 and has Marvell ARM based CPU. It is much faster than the Duo (v1), has the newer RAIDiator 5.3.x operating system. It also supports hard drives larger than 2TB, currently limited to 3TB only because 4TB drives are just hitting the market and there is no 4TB drive that has cleared evaluation for use in the ARM based Duo v2 and NV+ v2. However, this series is considered an entry level system and does not yet have the features of the higher level x-86 based ReadyNAS units (currently the Ultra, Ultra Plus and Pro series in 2, 4 and 6 bays). However, it would be a very good basic NAS for file storage.
I don't know what the price levels are in your market, but the Duo should be a significant discount from the Duo v2. Most likely the Duo v2 would be listed as RND2000-200EUS which would be for the European Union and would include power connectors for all included EU markets.
Remember - the NAS is not a backup plan.
Backup = Good, No Backup = Bad