Taking the 70 through Columbus it depends on the time of day. Early or late morning rush hour traffic can slow you down but as others have stated its a condensed area of congestion for only a few miles and then it opens back up. If your passing through on a weekend then no problems at all as I regularly do when coming back from camping.
Also I went past Indy last week to Turkey Run state park. On the way there I took the bypass which was fine and on the way home I decided to give the 70 a shot straight through...I should have taken the bypass instead. It was a saturday as well.
Hope it helps. if you need anything else just send me message and have fun!