My Thunderbolts are the only heavy mechs I own! Hey, I only own Tier-5 heavies!
At the moment I have the 5S and the 5SS left. Sold the 9SE lately because I needed a mechbay - had the least matches in it because I enjoyed the other two more and performed better in those two. And never had the free one because I was on holydays at that time :/.
Actually, the 5SS is the only one with a positive KDR, driving it more or less as a Brawler. (Std. 275, 2 LPLs, 3 MLs and 2 SPLs). Works for me. Maybe no one expected such a config on a TBolt, don't know. Or maybe no one ever saw a 5SS before on the field
(I'm pugging, and consider myself an average player at best, so Elo range can't be that high)
But more often than not, I'm not getting big attention in that 5SS, so they give me plenty of targets to melt. And when their minds change, I think they're quite surpised of the toughness of a Tbolt with a Std engine.
Oh, now we got the quirks, right. Had paused for a few weeks lately. Hm, have to look into that with the MPLs for the 5SS. Maybe there lies more fun ahead
As a sidenote:
Not a Tier-5 related mech, but the one I enjoy the most, and also have the best results with is my BJ-1DC. I just love that machine. And now I know why I perform so good i this one - it is a Tier-4 mech!! ha!