I don't know about pearls of wisdom, but general observations are free.
Several companies were showing some new capabilites for the GREEN movement. As with many companies, ELK is supporting GREEN Energy, but to some degree it is an application looking for an audience. The cost to put in GREEN Energy has to be inexpensive, because people are not going to put in equipment that has a 20 year payback on investment.
Ethernet IP is coming in all the technology areas. Get up to speed on using Ethernet in your installation or the world may pass you by.
The Apple iPad may change thinking on user interfaces as did the iPhone.
ELK was showing a new 2 amp supervised remote power supply, PS12S, which supervises the remote battery and AC input back to the M1 using the serial bus or any control using relay outputs. There is a programmable input and output on the power supply also.
The eKeypad iPhone software continues to get better and better with several new software version either ready or coming out soon. One version coming soon is for the iPad.
I was surprised that Crestron was not showing at EHX. AMX had a booth.