advice please, Best route Atlanta GA to Buffalo NY

That's not saying much.

 

The OH route is better in any weather. The Mountains in WV will get snow just about any time Columbus area does. On holiday weekends 71 gets slow south of the 271 split. Heck, most of the way from Columbus to Cleveland. I still like that route better though.
I drive parts of both allot.

 

B- has pretty good size hills once you get on 77 towards Beckley and there is a decent travel plaza up there, Its a toll road up through there too. I have ran that way up into southern Ohio, but my advice to you is behave yourself up in the Buckeye.