IMO the S3 would ski VERY different than the Mantra or Bonafide. I have not skied the latter 2, but skied the S3 (usually ski the Prophet 100 186 or Nordica Girish 185) and gave them back rather quickly. Good luck in your quest - I would ski them all and pick the one you like best (not what you read about on the interwebz) and 100 is not that fat. I appreciate the advice (and same from others) and in a perfect world I should do this, but don't know... I had to miss my locals hill's full-blown 2012 demo day b/c of a work commitment.
I ski the 110's now more than anything when it isnt frozen solid. I have a much different "helping" of hill compared to yourself.
Also, just a suggestion, you say you like to race, go look at the videos on Line's website and see if the 100 or 115 would not match what you want to do. I race on 66mm. If this was dry humor I shall check out the videos.
I'm actually now thinking more along the lines of 88mm... I know these will still carve, but be obedient off-piste and in crud (to a degree). These would be good to own, then if I go out west and get a 12+ inch day, I could demo a super-fat and see how I like it. I mean, from what I hear you guys saying for some days out there the super-fats are really the best (and I never intended--at least right now--on buying one of those... and those could get spoiled well if I were to acquire a 98ish ski).
88mm just makes more sense all things considered (like it is actually worth my investment where a fatter at this point wouldn't be). This will work when there are "deep" days locally and in NY (which they do have and all my skis amply sucked)... I'll need something and I'm not gonna be one of those people who takes an S7 to Boston Mills.
Dang... there's just a huge gap between 66mm and 98mm (partly why I'm leaning toward 88mm)... on that 66mm ski: jeez if it in not perfect firm groomed snow or smooth boilerplate the things don't have much use...
Sorry, not that anyone cares... I'm more thinking out loud.