I bought my Impala new at a Toronto dealership. I found the car to have good exceleration and handling. The 3.8L is bullet proof with over 360,000 klm on the original engine. The transmission has been flawless. The only issues I have had was with the computer which crashed right after the warranty expired. This was a $1000 repair. The wipers would not go into the park position, repaired several times. Most recently the gas gage went screwy and the turn signal shorts out on damp days. All in all an above average car that really doesn't owe me anything.
Favorite features would be handling and engine reliability.
Suggested improvements would be to the electrical components.