Yep, And the data to back up why they are better.
Okay, playing around in the data I'll confess to having underestimated them.
The Best Offensive and Defensive Lines in the NHL
moneypuck.com
Offensive lines only, min 149 minutes (yielding a perfect 128 lines, exactly 4 per team average).
xGA/60 they rank 12th. Damn good, sure. We did all know that. I use the xGA here to try and account for quality of competition- highly imperfect (look at the Canes lines's offensive rankings on xGF v GF for a sense of just how bad it really is) but the best offered here.
Goals (not expected, because the difference between expected goals and actual goals is not small with the Canes system and crappy finishing) for per 60? They rank 73. Which is decent in the 3rd line category. But if memory serves, nearly all of offense came early in the season, so that's probably biasing my view here quite a bit. Down the stretch and apart from Marty in the playoffs they were invisible offensively.
I still wouldn't call them the best 3rd line in the NHL though, since the defensive role they're elite at is still, at its core, a 4th line responsibility for nearly all teams.
Oh, and iterations of our 1st and 2nd lines are offensively ranked in the 3rd line range, and our 4th line is in the bottom 3rd of all 4th lines. Not good.