I was curious so I just looked up my review of Borgnine's Marty, and here's what I said:
While Ernest Borgnine is tremendously earnest and forthright as the title character, he doesn’t quite capture the same amount of deep-seated angst about his miserable single life and the repeated rejections...
I remember it fondly having reviewed the Criterion Golden Age of TV set that it was a part of. I haven't watched it in a long time now, but just from memory, I think I might prefer him to Borgnine if I compared them.