I always found both websites strange with their scores and reviews (or lack of reviews depending on what show we want to discuss) but I could never quite determine a pattern in how ratings seem to work. My theory is that shows on IMDb will have higher scores if the show is from a country other than Japan or United States. Then again, there is no particular pattern as it is more of a choice of bias in determining where to review the show.
I really wanted to compare the scores of the 1977 comedy Mind Your Language and the 2012 cartoon High School DxD. I was intrigued to notice that the former had scores of 9.0 (IMDb) and 7.5 (TV.com), whereas the latter had scores of 7.8 (IMDb) and 9.0 (TV.com). For those of you wondering, I love the former but have not seen the latter and probably will not see it for some time. It makes me wonder how to judge the overall ratings of both shows.
Also, which website is more preferable (for television reviews) despite being somewhat unreliable? And what score comparison is interesting to you?