Personally, I found it from a review at Home of the Underdogs when I was searching for some squad sim games. Even if I'm not terribly good at them, I love squad sims like UFO, XCOM, the Front Mission series, etc. Oh yeah, I also love giant robots...it's an anime thing =P
Now I will admit that despite hating 3D graphics with a passion, I am an extremely superficial person. And my first reaction was to see the screenshots and go "Droooool!".
I still maintain my belief that ToS has the prettiest interface of any squad game I've seen - even if the pilots aren't as cute as the ones in Powerdolls

So yes, I downloaded it - read the manual...got killed badly. Read all the documentation again. Got killed not quite as badly several times. Checked out the strategy guides - got killed only slightly terribly. Then I went to the forums and had a good old whinge - with those tips I finally started winning.
And yes. Now I'm here, the Mad Scientist of pessimistic ToS design and semi-newbie pilot =P