HAHA good question...
Ok, pure opinion and based on personal experience.
The GOOD designers (who are business) are insanely expensive (rightfully so) and focus on the full range of marketing products. The majority of Logo designers will likely be freelancing (to some degree) - and the very low cost ones are the free software/lead generators.
For the record I have at least 3 logo specific names, 1 good, 2 ok at best and have not really had any interest - 1 is listed on BB or BP cant remember. No bites yet and they are (all 3) very low on "traffic" compared to many of my others.
I Think (THINK don't know for fact) that the best "targets" for logo names may prefer something more overall marketing - and the DIY/lead sites are looking for the quick 1 hit logo as they dont have a bank of marketing resources or have the products to upsell.
Best of luck,
Brian