In Australia (which has 2 chambers - 1 under this system and the other proportional):

It is very difficult for a 3rd voice to gain traction. A party which has attracted over 10% nationwide for the past 2 decades, Greens, has exactly 1 seat out of 150 under this system.

We've had this method of voting for a century but voters generally see it as a binary choice - Roughly 35-40% will vote for A and 35-40% will vote for B. Typically there will be up to 5-10 candidates on the ballot paper. So that 20-30% of the "neither of major 2" could be split 8 ways across a wide political spectrum. Inevitably, most outcomes fall back to the 2 majors.