Hello all,
I just wanted to say thank you to the Ubiquiti team for the ER-X. Great job! 
Back when I purchased the first one for a client it was only because it was less expensive than and ERL and could handle CoDel on a 100/100 Internet line. I wasn't too thrilled about the lack of offloading, missing serial port, less RAM and less flash. I also discovered that it became a flat switch during boot. Even though it worked well (and still does) I dismissed it.
What changed?
With firmware 1.9 the ER-X offloads everything that I need (VLANs, NAT, forwarding and IPsec), I've played with it enough to realize that it has plenty of RAM / flash for my purposes and the flat switch problem is resolved. I was using about 18% or the RAM with an ERL and am now using about 30% on an ER-X with the same config. Also, I realized that a change in my setup habits / config backup habits / use of the reset button completely negates the need for a serial cable. As a side benefit it consumes less power, is smaller and with a POE switch doesn't need the power brick.
OK, OK to be fair DPI doesn't capture offloaded packets but I'm sure that a future firmware will solve this.
Amazing ... for about $50 we have a better version of the ERPOE. No, that's not true ... it's an ERPOE with a switch that can do per port VLANs!!!!!! If anyone points out that it can only supply passive POE on one port vs the five active on the ERPOE, I'm going to laugh.
best,
James