We lived about an hour from the total eclipse of 1995 so we … drove for an hour.
On the way we encountered a long line of cars traveling very slowly and parallel to the eclipse path. 
Most of them had already driven 15 miles from a large town closer to the totality zone. (I think some politico was offering an Eclipse and Fried chicken special, but doubt that those drivers ever got to the zone of totality, or perhaps just got a few seconds of totality.)
We left the traffic jam onto a deserted road marked “Warning: Road flooded.” I had to laugh when my passengers said nervously “At least it didn’t say road closed.” I’d been driving around scoping out the floods and knew: (a) (Bad news) Those signs didn’t go up until the road was impassible, but (b) (Good news) after the water cleared away it took about a week before anyone bothered removing the signs!
Based on my one total eclipse there’s a huge difference in darkness between covering 99% of the sun and totality.
If you’re not sure if you’ve seen a total solar eclipse, you haven’t.
Yeah, it’s pretty unmistakeable. I saw the one in 1999 from near Lake Balaton in Hungary. Looking it up, it was only two minutes to two and a half minutes long (looking it up), but it sure as hell seemed like a long time (I would have guessed 5 minutes myself.) It was one of the eeriest natural phenomena I’ve ever seen, and the difference between the minute before and after totality and totality itself was quite marked. 100% totality felt very different than 99%. (I even experienced a 95% annular–not partial–eclipse in Chicago in 1994. The moon did fully pass in front of the sun, but was too far away in its orbit to cover it completely. It felt nothing like the full solar eclipse I experienced five years later.) While it got quite dark, there was a quality to the darkness that didn’t feel like normal nighttime darkness, a “shimmer” of sorts, if you will. I also remember the birds chirping like mad a couple minutes before totality, basically settling into their nighttime routine.