Synology has a new model in its lineup, the DS1520+. It offers space for five drives and has a 4 core processor on board (Celeron J4125 with 2.0 GHz). 8 GB RAM are included.
Although the device offers four Gigabit ports and also 2x eSATA, we unfortunately have to criticize that there is no 10 GBit/s port on this model as well – neither in RJ45 version nor as SFP+. It can’t be upgraded either, because the model doesn’t offer an expansion slot. However, if you are not interested in this, because you have many separate users using the device at the same time, you can access it.