The size difference between the E-Series and the standard (including C-Series) is significant in my opinion. The debulking and unhefting that the E2e has been through really makes a difference when carrying it compared to the C2 clipped inside your pocket.
Why get a C2 over an E2e?
Ability to use the P61 High Output Lamp Assembly.
Ability to use the CombatGrip.
Ability to more ergonomically grip the flashlight in high-stress situations and/or when wearing gloves, in the cold/wet where a larger flashlight is easier to grip and operate.
Ability to add the as-yet-unreleased KX5 LED bezel.
Beam is more intense although the difference is not massive (IMHO)
Why get an E2e over a C2?
Much smaller (in length, thickness, weight & bulk/heft)
Easier to carry pocketclipped whilst wearing light-weight clothes (such as suits)
Ability to use the KL4 bezel and as-yet unreleased KX1 LED bezel.
I would suggest that as a general EDC the E2e wins out.
If you actually need to carry and use a flashlight, especially in high risk/stress situations then a C2 or Z2/G2Z could be more useful.
Al