I picked up a Growler 40 and specced it out this past season. I absolutely love it! Hardtails have their own magic. I'm riding everything I did on my last bike (a big travel full suspension enduro bike) but having more fun and getting a better workout.
Finally added a Fox 36 for next season and I can't wait.
You can check out my Rocky Mountain Growler Review.
If you want to see how I built up the 40, you can have a look at my Rocky Mountain Growler Custom Build.
Little late to the party, but maybe this info will help others in their bike shopping for '21!
I agree with the article, that the Growler is flying under the radar, but I'm sure as more people try modern geo, on value-packed builds, these aggressive hardtails will only get more popular.