I suspect that in most cases he writes a review on something he personally likes. I doubt that anyone would take the time to write one on something they hated unless they felt very strongly about it.
Actually, that was what I did in all cases. Personally, I feel like I couldn't sit down and write about something I didn't like. First of all I was raised to believe that "if you can't say something nice, don't say anything at all" (OK, so I don't always succede there-but I try). To that extent, I don't want to publically denounce someone else's hard work, all that does is discourage a designer who is doing their best and giving away the product-I feel an action like that would be beyond rude. Plus, why pick one of the thousands of different addons and write about why someone shouldn't download it. I enjoy flying these planes, and if I find one I really like (especially if I have time to write), I like to share my feelings with other simmers. I look at it as a way to thank the desiger-a way to say "look at this one because its really special." Anyway, I enjoy writing about the addons that I especially like and hopefully people out there like to hear what I have to say.
Also, I do plan on writing more-it just comes down to when I have the spare time (I'm a Biology student at the University of Oregon so they give us a pretty heavy work load).