Strangely, perhaps, in general. I've grown to appreciate the Beatles, but I never loved them, and it was a big reason why.
I got totally into the 'Stones before I got into The Beatles. I think the "which group was better" arguments are basically pointless, because for one thing it is like comparing apples to oranges. I would guess most fans who got into the Beatles first will never fully appreciate the 'Stones, and vice-versa.
All that being said, I think Lennon had a fine rock and roll voice. Rock and roll, the good kind, is more about feel than technical proficiency, anyway. I used to listen to some of Joan Baez' renditions of Dylan material. Baez had a great voice, and her version of a song like "I Shall Be Released" was beautiful, in its way. But the raspy-voiced, oddly-inflected original had all the power and emotion and "feel" the cover version lacked. You can guess which one I favored. When Lennon was "on", his voice could be very emotive. I am not personally a fan of anyone rehashing their primal scream therapy on vinyl, but the first LP with the Plastic Ono Band is full of powerful Lennon vocals, on songs like "Working Class Hero", "Well Well Well", etc.
I don't like "Imagine" either, for complicated, visceral reasons I really don't entirely understand. I just think it is bad Utopianism, or something (as opposed to "Give Peace A Chance", for example, which I quite liked.) And I don't like to see Lennon promoted at McCartney's expense (because I think McCartney was as important to the group as Lennon, and was an equal as a solo artist.)
But I cannot knock Lennon for his voice. As has been pointed out, his vocals on "Twist And Shout" alone are classic.