After watching ep 3.5, I have to say, again, Chris Colfer rocks. (And how adolescent *that* sounds!) He seems a little over the top when playing the everyday-Kurt, but I so have met that kind of people, that seem too exaggerated and arrogant and loud, but are mostly too afraid to be real, to be rejected (probably because they have already been rejected). Because they know that any vulnerability that you show could be turned against you. So, when Chris plays Kurt I believe him, but I stand in awe when the most serious, dramatics scenes arrive, and all that we could glimpse before comes to the fore and you can feel his depth.
So, yes, Colfer rocks, singing or not.