Not just ears but breathability also.
I find that the ears tend to get a bit more dirty on my events since its a separate porus material (soft ears) vs one giant piece of flexible rubber for the avatars.
The avatars are similar to the older style events from 08 where the mouth grill doesn't have as much room , compare the pictures, you will see that the 09 events curve out more. I find that, for whatever reason, maybe old age, I cannot use my avatars/older events anymore since I literally cannot suck enough air down my lungs with them on while I'm playing. You may wish to consider the 09 events or eflex if you have a large air intake.
All the events type lenses fit on everything from the entry level helix all the way up to the newest events. Same lens, just different comfort depending on the rest of it.