I came from a 2011 S4 (DSG) and previously owned an RX-8 R3, Miata, and WRX, so I'll do my best to compare/contrast. prepare for a stream of consciousness...
1. transmission - the manual is a joy, the distance and weight of the throws is as perfect as I can imagine. the shifter is right where you expect it, at the proper seating position, it is right in your right hand.
2. clutch - it grabs high, almost at the top of the range of motion. that means it's much more of a knee/leg action than foot/ankle action. i'm still not completely used to it yet. i've accidentally revved at other cars when shifting into second and gassing it before i got off the clutch.
3. active rev match - another joy, it works so well, it makes driving a manual so much easier. it's so easy for me to select the right gear no matter if i'm braking or coasting. it's especially fun when your exhaust is on track mode.
4. hill holder - working in Seattle, this has been a god send. it takes a little while to get used to, but once you do, it's hard to live without. it takes all the pressure off when you're at a stupidly steep hill and the guy behind you is right on your bumper. it is implemented well, turns on when needed, and does not activate on slight inclines.
5. visibility - it's not great, but it's not as bad as people say. if you properly adjust your seat height so that you're two inches below the roof of the car, you can be a perfectly aware driver to what's going on around you. you MUST adjust your side mirrors to cover your blind spots because you won't have a blind spot monitor. the hard part is that it's not easy to see the corners of the car, so pulling into spots and narrow places can be challenging. i think in time you get to know the size of the car, and that becomes less of a problem.
6. exhaust - my 8 year old self loves it, it's just so hard to not smile when you listen to the exhaust. it's just that classic muscle car sound, and for some reason brings a smile to my face every time. dat startup sound, hnnnggggg... the throttle liftoff burble, hnnngggg....
7. back seats - they are a joke, my 3 and 5 year old barely fit with their booster seats. they endure it to sit in daddy's "race car", but it's pretty small back there.
8. ride quality - mag ride is incredible, but the OEM tires are very stiff. I'm running 19"s for my winter setup, and the ride is excellent with them & mag ride on touring mode. it's a bit on the stiff side on touring with the OEM tires.
9. driving dynamics - whether you know it or not, you're probably used to your car understeering a bit. to get my S4 to rotate, I would actually have to lay on the gas to get the sport diff to rotate the car. the 1LE is not like that, it WANTS to rotate. it wants to go where you tell it, so just tell it where to go, don't try to muscle it like you may have needed to in a prior car.
10. stereo quality - it's not very good, but over time you'll forget what a good sound system (like B&O) sounds like. then you'll be decently happy, and if you're not some folks just install an aftermarket amp to bring the stock speakers to life.
11. window switches - ugh, why are they so far back? as someone who parks in a garage daily, it's annoying.
12. storage - good grief, it's hard to get to, and there's not a lot of it
13. HUD - it's awesome, makes it so much easier to never take your eyes off the road.
14. power - it has more power than I'm willing to use on the street on an all season tire setup in winter. i'm surprised there are guys who want even more.
15. seats - great seats, just wish they had lumbar support. to give you context, i'm 5'11", 195, with relatively broad shoulders and wear a 34" pant. i do wish i had a bit more room in the upper back/shoulder area, but they are really good. better than the S4 seats, not as good as the RX-8 R3 seats.
16. width - it is 75" wide, and you'll feel the extra couple inches coming from a BMW 3 series. i def feel it coming from an S4. you're also sitting more in the middle of the car, and you'll feel that too.
17. powerplant -
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18. MPG - i average a mix of 3 highway miles for every 1 city mile, and the best I've gotten is 23 mpg. it's worse when i just feel like listening to the exhaust instead of the stereo.
overall, it's an excellent car if you want to be engaged when you're driving yet comfortable when you just want to take it easy around town. however, I have not found it to be relaxing. I could have a relaxing drive in the S4, but I can only be so relaxed in the Camaro, maybe it'll come with time.