My own personal experiences with energy have occurred along a continuum from negative to positive and included audio, visual and emotive type 6th sense perceptions. The audio experiences were relatively neutral (hear my un-edited EVP here). The visions were not (see entry, Was This an Angel? for more info.). The experience of positive and negative in the form of light and dark made an impression on me.
So, while I am not necessarily skeptical of mediums, I am not completely comfortable with them either. When listening to the Abraham Hicks audio, for example, I couldn't help wondering who I was actually listening to. Having no first hand experience of this energy, I have no real sense of its place on the spiritual spectrum. I don't consider the energy mediums tap into dark necessarily. I'm just not convinced that it is the best font of spiritual info available.
I am not dismissing channeling completely. It is my opinion that some mediums (such as John Edward who I have seen live) do it well and that others are yet to be proven. I am always curious about channelors and channeling in general. I find the Law of Attraction as presented in the Abraham Hicks material and elsewhere fascinating. The presentation may be simplistic but, based on my own experience of light and dark, I agree that there does appear to be some degree of reciprocity between our energy and what we connect with on the spirit plane.
I have heard mysticism described as an attempt to reconnect with the creator or source energy and for me at least that's accurate. We are all chasing something in a spiritual sense and the medium offers us glimpse of what we are after. It is not the same as personal experience however. We may have questions about the validity of the information. And if we are to attempt our own channeling, it is worth noting that auditory, especially verbal, psychic phenomena is sometimes quite close to thought.
These are the reasons for my reservations in regard to channeling. And I think it's important to apply our own individual intuition and discernment to any channeled information we receive (whether directly or through a medium). The best way to improve our intuition and level of discernment IMO is by raising our own energy through meditation, study or prayer.