I have a 2015 Z51 A8 I picked up in October 2014. It was a rainy day so I drove home in weather mode the car was awesome compared to the C5 I traded in as far as driving in the rain.

I used the paddle shifters to slow down in curves right from the start, also used them on the first road trip the next weekend in the NY wine country. Was so excited when you could "tach it up", too bad it was on the way home.

Here is my take on the A8.
Two years 7400 later miles the trans shifts from park to drive seemlessly
the performance shift mode is awesome stab the gas and bang you are in the right gear stays there for the curves, lots of fun and faster than paddle shifting.

The only con I've had is when slowing down almost to a stop then stepping on the gas it has an odd shift, like it was going to 3rd then goes to 2nd. Not every time mostly when cold and hard to reproduce.

Basically If I didnt read this forum I would not doubt the A8, My 1986 auto with a shift kit shifted harder when cold and jerked harder from R to Drive.

 

I got my 2015 in the beginning of Oct 2014 and now have 14,000 miles. I hope you have one of the good A8s because my problems started at around 9700 miles. Up to that point I followed all the posts on here about problems and hoped I would not have them. I am currently trying to find a dealer in NJ that has done this repair before.

 

A Great? M7 Heaven.

 

Five days short of one year and 9600 miles later, I too am loving my A8. This coming from a die hard manual guy. First Corvette was a '87 A4 slushbox. Swore I would never have another auto Corvette. After twelve years of M6 bliss and a deteriorating shoulder following surgery, I decided to give the A8 a try in my 2016 non-Z51.

Spent the first three months worrying about all the things I read on the forum, had the transmission reflashed once because of slow engagement and rpm variation. The reflash improved those issues and I finally decided it works the way GM designed it and I could live with that. The biggest reported "problem" issue I deal with is the slow engagement first thing in the morning. I solve that by starting the car on first entry, then hooking the seat belt and waiting for the gages to finish their startup routine before putting it in gear - problem solved.

I drive mostly in "D" because this awesome transmission shifts a lot better and faster than I do, and in normal driving is almost always in the appropriate gear. When taking the twisties with a little spirited driving, I like to downshift with the paddles before the curves so I don't get the lurch you sometimes do when gassing an auto with the resulting downshift coming out of the curve. Then I upshift a gear or two with the paddles and optionally hold the upshift paddle to put the transmission back into full auto. Otherwise, I don't paddle shift a lot, mostly because this transmission can do it a lot better than I can. Also, in manual mode, I really don't like the excessive delay on the 1-2 paddle shift (sometimes as much as 1000 rpm) but others are acceptably quick. Track mode and/or heavy throttle application reduce any perceptible delay to just about nil though.

Never had a problem with the V8-V4-V8 change, it is completely unnoticeable unless the transmission is simultaneously shifting gears and you get the slightest lurch. V4 operation is smooth with about 50 rpm variation on the tach cruising down the road, but this is designed into the TCM control of the torque converter if my research is correct.