RE: What percentage of the replies are worthwhile?
All in all this forum is a tremendous collective pool of knowledge, experience and information.
The "Catch 22" is that you have to already possess a certain degree of knowledge and experience in order to distinguish the useful, accurate info from the brand loyalty or brand bashing ramblings.
The more one knows about engines the more help one can receive (by knowing how and what to ask, for example).
David