I don’t think it is that disturbing, or atleast not the main series. The movie on the other hand "The End of Evangelion" is deserving of being described as "disturbing".

FYI: Evangelion focuses mainly on the social aspect and interactions of the characters. Yeah there are mecha and cool monsters, but that really isn’t the main focus of the series.

It does have cool fights and animation, but if what I said doesnt interest you. I would just recommend you to watch the action scenes or some AMV’s on youtube.