Ditto. The Omni-VI is a better rig in many ways than the IC-751A is, although it's also larger and takes up more space.
Since the only transmitter I have here is an IC-751A, I'd appreciate hearing why you say that.
Pretty big difference in technology, there. The OMNI-VI is 6 years newer. Operationally, I love the direct pushbutton band selection; switchable (from front panel) separate receive antenna jack; 10 Hz digital readout resolution; 100 memories that store frequency, mode, filter selection, RIT/XIT data and split status; true QSK without waveform alteration to 60 wpm (the 751A is good up to about 20 wpm before it starts clipping the envelope); and other PUI features lacking in the 751A; however in terms of performance, focusing on receive (measurements all by Sherwood Engineering):
OMNI VI 2 kHz dynamic range, measured: 80 dB
IC-751A 2 kHz dynamic range, measured: 64 dB
OMNI VI 20 kHz dynamic range, measured: 97 dB
IC-751A 20 kHz dynamic range, measured: 84 dB
OMNI-VI L.O. noise, 20 kHz spaced, measured: 137 dBc
IC-751A L.O. noise, 20 kHz spaced, measured: 127 dBc
OMNI-VI Blocking dynamic range, measured: 145 dB
IC-751A Blocking dynamic range, measured: 138 dB
review (January 1993) of the OMNI-VI has a remarkable statement which I've found to be quite true: "The Omni VI's synthesizer is one of the very cleanest in any modern transceiver" (page 67 of the review), and this shows up when listening to weak signals on a crowded band. It's easier to hear them, and less tiring to listen to.
I've had both and would greatly prefer the OMNI-VI for almost any kind of operation, with two limitations: It doesn't have "general coverage" receiving (which the 751A does), and it's larger, and takes up more space than the 751A does.