It seems not that well-regarded, as almost all old two-transistors-only phono amps to be found in just about any old receiver. Maybe putting in more effort to have one better one instead of two. Who ever has two turntables playing at the same time....since there are two separate phono amps in the TR2075.
I bypassed one Phono input to have an extra input on my TR2075, one of the two others I bought were modified also. At the time I bough my first one, almost 40 years ago, modifying it was already a known and common thing.
I think the TR2075 was state of the art in 1975, except for its phono. They did not even use a single low-noise resistor in there.
I have never had any high end turntable, but I do remember for me the sound was definately good enough (not having a turntable for over 35 years, now).
So, well-regarded or not, just enjoy it.