User blog comment:Nweston8/Robot Wars Missions - Entry 2: Finding machines that are genuinely underrated/@comment-6279140-20171222182517

I think Big Nipper. Nearly no one seems to remember it and its often defeated early on. Prior to its series 10 campaign (and even then Eruption got a lucky break in defeating it), Big Nipper was hardly in anyone's favourite robots page, despite being an FRA champion.

I'm also adding Beast. Also all of robots it faced became a success story before or after robot wars ended originally, with the robots that defeated it in the early wars being seeds and the ones in series 8 were pretty much veterans in their own right.

Honorable mentions: Turbulence and Merlin.