I have done both routes. However, both were in the 80s so take that into consideration. At that time, both routes had similar amounts of traffic, hazards, etc.
I really do not remember any major area of concern compared to the TA other than Glacier NP had some heavy traffic but it was quite doable as the traffic speed was fairly low. I also dipped directly through Minneapolis/St. Paul so that obviously was busier but I planned it accordingly, i.e. rode into town in early afternoon and out of town on a Sunday. The traffic for a 20 mile radius around Cleveland (at that time it went thru Cleveland) was heavier also.
ACA does a pretty good job of staying off overly busy roads. Sometimes there are just no alternatives. Also, it may be partially due to today's litigious society we live in.
All in all, I would say if you handled the TransAm without difficultly, you should most likely be able to handle the NT. After all, you have crossed the country before so give yourself some credit .