Ratings: I try to rate opinions based on how much value they add from the perspective of a person trying to make a decision based on the review they are reading. I find reviews that contain information about personal experiences and specific feedback much more useful than very long reviews with lots of general information that is readily available on the web, shopping sites, etc. I do think that many of the raters on Epinions are being extra tough on negative reviews outside of Books and Movies areas. If you had a negative experience, and if you explain in detail exactly what you did not like and what went wrong as opposed to just ranting and raving, you would get at least a HELPFUL rating from me.
WOT: If you considered my reviews worthy enough to put me on your WOT, thanks! I try to add people to my WOT based on the quality of their reviews. If you added me on your WOT, I will at least try to read a reasonable number of your reviews. If you have reviews with interesting and/or useful information, good writing style, and most of all, if you are being honest about your opinions, I will likely add you to my WOT or at least keep an eye on your new reviews.