I just want to go on record that I don't necessarily take GURPS as gospel. GURPS is a fine resource but it has been designed as a Role-playing guide, to be used as a Role-playing guide. Sure, there may be a lot of information here, but it doesn't always mean that it is 100%, just as any text.
After Ares' post, I tried it out for myself. He's absolutely right. The Forest Giants smite smaller units in approximately 40% less attacks than a Trow. And they beat Trow senseless in one on one. In pitting Three Trow against Two FG's: 80% of the time an FG was still standing. 20% of the time both FG's were still standing!
So to answer the original Question: Trow vs Forest Giant?
Forest Giant it is, baby!
Zandervix