Just my thoughts, for what it's worth.
I notice that they have a graph you can click on for the EP400, EP500, EP600, but none for the lesser models. That right there tells me that the frequency response on the EP125, thru EP350 are not as even as the others.
The loudness for 350 vs 500 are almost the same in decibles, but if you are going to play it loud, or in a bigger room, then the 500 would be the better choice because it has DSP.
So, I would say, if you want a more accurate and cleaner sound, go with the 500. If not, and you want to save money, go with the 350, because it will sound good also. Probably the only way you would even notice the difference is if you got used to the sound of the 500 first.
