I wanted to share how happy I am so far with this model and report some results for those considering one.
I think that Channels runs smoother and faster on this than it did on a Quad core I7 CPU. The commercial skips and channel changes are brisker and much shorter than when running on a cpu.
The USB 3.0 port is wonderful. There were some questions I had on whether or not I could use it with an 5 bay external Terramaster docking station. I'm happy to report that as soon as I moved everything over and plugged it in to the system and mapped, it worked flawlessly. You do have to install the exFat file package from Synology, but it works great and I have full access to my movies as they were without reformatting any of the drives.
The DS720+ has SSD cache acceleration which I could've passed on and save a little money unless you have allot going on over your network ( I really don't) but if you opt for a machine with it you can always use it as extra storage, I've got another 2TB of storage there if I need it.
I am running 2 1tb SSD's in Bays 1 and 2. I think the direct connection really has helped with access. I would recommend them, between me and the wife we are using about 20% of 1tb for recordings we just haven't gotten through yet.
I would definitely recommend spending the extra money for a quad core and get the extra ram but overall I wish I had done this years ago. I'm extremely happy with how well channels performs on this system.