First of all, Schubert make helmets that fit my headshape, there is no "one shape fits all", you have to try different brands/models.
I've been using a E1 for three years, also coming from a C3 pro. I find it quiet for a helmet with a beak, (i always use earplugs ).
I love the beak in low sun conditions, and that you can remove it if you want to really burn gas on the autobahn.
The only downside is that I miss a air vent on the top to get rid of heat like on the C5 and E2. It is not a major problem her in Norway, but i notice it when travelling to warmer climate.
I'm seriously thinking of buying a E2 just for that reason.
If you also include that the E2 is ECE 22-06 certified and has better ventilation than a C5 and is quieter than a E1 (according to Schuberth), I think the E2 is the one for me.
The main reason it has not happend yet is the i find the colors dull, I like bright yellow that is easely seen in traffic.