I would like to upgrade my NAS. For sure, I don't want to replace my current one (a Synology DS209+ II) by anything else than a Synology. Currently, I would chose a DS713+.
The new version of DSM, 4.3, is not supporting anymore my old Synology DS209+ II, bought in mid-2009. But this is not really an issue as packages will continue to be updated on DSM 4.2.
I am mainly looking for an new NAS to increase access speed.
The DS713+ has 2 Gigabit Ethernet ports with support for nic teaming, Dual Core 2.13GHz, 1 GB DDR3, 1x USB 2.0, 2x USB 3.0, 1x eSata, Sata III, 88.6MB/s write and 55.7MB/s read speeds (Those are mean values as it depends a lot on the RAID config, disk type, size of the transferred files, link aggregation, ...).
My old DS209+II had only 1 Gigabit Ethernet port, 1.06Ghz CPU, 512MB DDR2, 3x USB 2.0, 1x eSATA port X1, Sata II, 50 MB/s write, 60 MB/s read speeds.
Look here for DS713+ performances.
But the DS714 is coming soon... It will not be as fast as the DS713+, but using an Intel Atom CE5300 SoC , it will come with hardware HD-video transcoding capabilities, which is interesting if I want to run a media server similar to Plex. It will be a Dual Core 1,6GHz, 1GB DDR3, 3x USB 3.0, 1x HDMI, 2x Gigabit Ethernet ports.
I will wait until the DST174 is out to read the first reviews comparing that new model and the DS713+.
I considered to buy Seagate ST2000VN000 (HDD Seagate NAS 2TB SATA 6GB 5900rpm) HDD's as they are 40€ cheaper than the WD SE WD2000F9YZ (7200rpm) HDD's. But I finally took the WD as the warranty is 5 years (instead of 3 for Seagate).