The DB8 is NOT a dog. When he bought it years ago, it was one of the best UHF antennas available.
Every reception location is different. The goal is to pick the best antenna for THAT location.
It is primarily the tilt feature of the 91XG and HDB91X that makes a difference at his location. The DB8 doesn't have a tilt adjustment; it would be a custom modification.
When I was making antenna tests at a location that had a clear LOS path across water, I found that tilting my 4-bay UHF antenna increased the signal strength.
