Hi,
I have not used a Kenwood so I can not comment but I can in regards to the Ic-751A.
I own one and love it. My main band of operation is 10m. The RX is in my opinion outstanding and the Notch and filter functions really work. The TX is also in my opinion outstanding too. I run mine with an Ic-SM2 Desk Mic.
I also own a newer Icom HF radio and I would never let my Ic-751A go. In their day they were the rig of choice and to this day are still sought after.
I use mine all the time and it has never let me down. If you can get hold of one I would recommend you grab it! You will not be disappointed.
That’s my 20cents anyway.
73 Dave