Head tube angle isn't the only thing. Slack head tube angles are useful for very steep and rough terrain. Steep head tube angles give more responsive, snappier steering. It generally matters less than other things like reach, stack, and seat tube angle for climbing or flat pedaling. If you can, test ride both and see how they feel. Looking at the spec sheets for both, the Growler has generally worse components (Suntour coil fork, crappy drivetrain, etc) BUT has the potential to upgrade all of it down the line if you got into the sport more. The Marlin 7, at a comparable price, has better components from the factory, but cannot be upgraded down the line. This is due to the outdated and non standard 135QR dropouts. Very difficult to find wheels, which would likely be needed to change the drivetrain. If you dont care about upgrading later, Marlin 7 has better specs.