This transmission is different than anything else you've ever driven. That being said, my 2015 has already 4 trips from Québec city, Canada to Miami, Florida with nothing to worry about. The "surge" described above is a normal behavior for these transmission and has been documented on this forum a couple years ago. I don't have time to find the post now but a search would probably allow you to read on the "surge".
the dog clutch is not between 1-2 and 7-8 as stated above, the dog clutch is between 4th and 5th and will shift hard sometime when the car is cold (I mean Canada cold). this is a weird feeling when it shifts hard but completely normal, just go easy when cold if you live somewhere that has a winter season.
The 2nd to 3rd hard shift is not experimented by everyone and can be somewhat fixed by a software update. Some will tell you that the update didn't fix it, other will tell you that the update works.
Accelerating quickly to 60MPH and 6th gear and letting go of the gas is not a normal driving situation and the transmission will get lost sometime between 4th, 5th and 6th because the ratio are very close and it doesn't know in which gear it should be but Under normal driving conditions you will not feel anything wrong.
this transmission is not perfect but the V6 version of it has proven after 4 years to be reliable if all the recalls are done and all the updates are done.
I hope this helps.
Very helpful information. Thank you!