The grove system is nice, but, it is heavy and, believe it or not, shorter than the bungee gear. This makes the bungee gear actually better in the bush. Weight is the enemy in STOL performance.
Remember, your example was 80 kts. That equates to 92 mph. This is not far from the mark I gave for my plane. Depending on rigging, farings and prop I see nothing outrageously out of line about this speed.
90 mph is a real easy cruise at ~4000-4500 rpm with my yellow plane.