The phrase "comparable only to" is correct and usable in written English.
You can use the phrase when you want to compare one thing to another, suggesting that the former is equal to the latter in terms of quality or importance. For example, "The Grand Canyon is a sight comparable only to the Great Barrier Reef in terms of scale and grandeur."
The achievable resolution is comparatively low, and results derived from the reconstruction of internal structures are currently comparable only to manual dissection.
The outpouring of affection from the center's staff was comparable only to Ms. Coppadge's energy.
What strikes one travelling around Japan is the affluence of the place, which is comparable only to the United States.
The major outcome of that competitive activity is profound relaxation (comparable only to that produced by spinal anesthesia).
Point-of-care (POC) rapid HIV tests have sensitivity during the "window period" comparable only to earliest generation EIAs.
Arguably, research into ceramic biomaterials has reached a level of involvement and sophistication comparable only to electronic ceramics.
Because of its general usability, his manual has long enjoyed a popularity in the West comparable only to that of Gray's Manual in eastern North America.
The losses that investors are suffering this month, he wrote, are comparable only to those in the 1960s and during the bursting of the Internet bubble.
Napolitano said during Holocaust Memorial Day commemorations that recent insults made against the Jewish community were "comparable only to the repugnant material in those packages".
For about half a decade at his prime, Bachar enjoyed a reputation comparable only to that of Royal Robbins in the 1950s.
GDP has collapsed by more than 30% since its peak before the crisis: a decline comparable only to that seen in the US during the Great Depression.
