I only tested 6.1.7 in the LAB, so far no issues fpund on that SW version.
The EDM on the ERS5000 had a big improvment since SW 6.2 release.
I also use the CLI for the most task, but JDM EDM is a good additional tool for some task.
With SW 6.2.3 the EDM has very good repond times, and feels much smoother than it was before. I personal still prefer the JDM, in fact I am more used to it.
In combination with the COM you get the best performance out of the EDM. On COM you have a .war file that includes all the code and communicates with your switch with SNMP,
like the old JDM. So the web server that is running on your switch (wich is the bottleneck from the performance point of view) is not needed. All the graphic output is handled by your COM server.
Cheers