I used to be a big proponent of the 79-39 route instead of the OSR-39 route. Reasons I changed and haven't gone back:
1) 39 is fast. Unless you get stuck behind someone slow and opposite traffic is just heavy enough to make passing difficult or if you're stuck behind 5 cars all cool with the slow pace making passing too complicated.
2) With the speed limit on 45 up to 75 (meaning really 80), more time on 45 is advantageous.
3) When I was taking 79, I always saw cops there. Got one ticket on 79.
4) OSR sucks, but you're only on it for 8-9 minutes.
5) If you or a travel companion is the type that needs a restroom stop while on a sub 3 hour drive (my wife), Woody's is a much better place to stop than the s-holes in Buffalo.