[Lalaith]

I would agree, Form. If we measure power for example in terms of being "a great character", Feanor is greater than Galadriel.
Also, while she was superior, morally speaking, his creative spirit was greater.

I always remember the first time I heard Feanor mentioned, when Gandalf talked about how he longed to see his hands at work, via the Palantiri. I thought at the time, if Gandalf has such admiration for him, well...