I haven’t used that chip before but the slew rates on the datasheets for both chips look significantly different (6V/µs vs. 3000V/µs on the LM6172).
You could pretty easily compare them if you just breadboard a buffer circuit like this (remember 100nf bypass caps on V+/V-) and feed it signals with hard edges like a keyed shape or hi frequency square wave oscillators. It should be readily apparent on the output if the NJM2068D isn’t slewing quick enough.
The 1k resistors on the op amps are suggested in the LM6172’s datasheet for buffers. Not certain if that’s required for the NJM2068D or if you can get away with a wire link like in a TL07x buffer circuit. Let us know what you find out if you try this!
