Very interesting and a little surprising. I too expected better from Rane.
To give a bit of background on this preamp, it came from a radio station. They had a bunch of them, and I was told that it was the standard broadcast phono preamp of its time. Maybe that was or was not true generally, but it was for this station.
The main reason I stopped using it - replaced first with the Emotiva XPS that Amir also measured, later with an iFi iPhono because I think it's cool it offers different EQ curves for different types of pressings - was that power supply. I like to unplug when not in use, and Rane has a phone/network style plug that feels fragile and can easily snag.
Back in the day, the subsonic filter was engaged in order to save amplifier power. And this was before the ubiquity of subwoofers.
You want a subsonic filter if your system has bass extension like this (Dirac through Bryston SP4):