For a compact car, I do not think it is any louder then anything else on the market. My Previous vehicle was a 2012 Honda Civic EX and it was pretty much the same. The car is a great deal for the price, I went for the limited since it was worth it for a bit more money. It is not performance beast but it moves along just fine. I have 3K miles on mine now and I average 33.6 MPG- I think this is great for a all wheel drive vehicle.
I have 8,000 miles on my 2015 Impreza and it has been a great car for its intended purpose. Make no mistake though, it is not a powerful, quiet highway cruiser. It is a perfect around town or city car. If you drive on the highway everyday you will notice it is very twitchy at higher speeds and is very sensitive to sidewinds. It seems hard to keep it going in a strait line. Also, the Bluetooth/ touchscreen is terrible and slow. The front seats do not have a lot of legroom for taller people. All in all, the gas mileage has been very good, and it is reasonably fun to drive. My advice, get a base model because it feels like a $17,000 car, not a $25,000 car.
We never buy a new car but when shopping for an Impreza, low mileage used were always more than new. So we ended up looking for a new one, with acceptable colors and price. Never found much difference in price and shopped internet in 4 states. Never found the desired color in stock but winter was coming and wife wanted all wheel drive so we made the purchase locally with an acceptable color. I've been a "car nut" since the 50's and have owed many from a full race Pontiac to a Mercedes and BMW but never a Subaru. The Subaru Impreza drives with the best once you replace the factory tires with good ones. I don't find the noise objectionable even under heavy throttle. The body has some flex which was disappointing but not unusual. Car is well made and solid overall. Subaru produces vehicles in various models but the option list in each model is sparse so don't plan on adding anything later from Subaru. The CVT ruins the car for me but the wife still loves it. It requires a different type of driving. Maybe I'll get used to it eventually if my wife ever lets me drive it. Mileage is great with warmer weather. As with all vehicles, it's not great when it gets cold. About 37 MPG highway in the summer and 27 MPG for shorter travel. The vehicle mileage indicator isn't as smooth as other vehicles and is off between 6 and 8%. For an economy car with all wheel drive, the Subaru Impreza is a best buy. Update after two years of ownership: The Impreza is still a best buy if one is looking for a practical, inexpensive, AWD sedan. It doesn't have the bells and whistles but it would be hard to beat it's mileage, driveability, and practicality for the price. I'm still not a CVT fan but it looks like that's the best way to obtain the economy. Cold temps really drop the mileage but that happens with all vehicles. The car is built well and materials are durable. Seats are comfortable and no wear is showing after two years. Plenty of leg room in the back seat for a small car. Other than the CVT, complaints are pretty minor. The painted front is not very durable and results in many paint chips. It could use more insulation and sound deadening material throughout the interior. The windshield seems thin and rock chips spread rapidly. There are times when a little more height would be nice for visibility and clearance but Subaru has models to provide that feature. All things considered, the Impreza does everything well that it was purchased to do for us. It provides economical and dependable transportation for all seasons and road conditions.
I've owned 3 different cars in the last 10 years and I have to say the Impreza is one of the best ones I've owned. The ride is very comfortable, interior is extremely nice to be in, and the styling is very nice too. Currently I am getting 42MPG (mainly a highway driver). The car does not feel underpowered getting up to highway speeds however do not expect WRX acceleration or sounds.
I traded in my old Scion XB from 2003 for the sport Limited hatchback and i have to say im very impressed if it had 20 or so more horsepower i would be one of the best performing compact cars on the market. The CVT itself isn't really that bad unless you floor it or when your going on the highway but other than a few slow shifts it is a great car overall. I live in Buffalo and the AWD is great for snowy weather.