Faults:

Nothing.

General Comments:

Extremely underrated car.

It looks fantastic, very well built, top reliability, well designed cabin. Performance is incredible, blows anything classified as 'fast' into oblivion. Instant power on tap - nearly electric-like. Caution required even in the dry with RWD, as you can spin the wheels very easily. Terrible in the snow, but that's expected of any RWD car.

Faults:

A dark paint spot on the bonnet, fixed under warranty.

Rattles in the dash area.

General Comments:

Much much more reliable than my previous Audi A4 2.0 CVT, and doesn't consume excessive amount of engine oil like the Audi does. Much cheaper to keep and run than the Audi.

Quieter and comfortable, handles well although not quite up to BMW or Merc. Good equipment level, cooled and heated front seats. Nice and smooth engine + transmission. Suspension is on the soft side, but gives a comfortable ride. 2.5L engine is adequate, and only consumes around 8.5L of fuel around town at an average speed of 50km/h. Rear seats are comfortable, but leg room is not great.

Only complaint is the rattling and squeaking noise coming from the dash area and the moonroof in summer time. Front of the car is prone to stone chips, and the paint work is not as good as my previous Audi.

Boot is fairly small, and rear seats cannot be folded down.

Faults:

Dashboard and doors squeaked then rattled (seems to be a common problem among IS). Took it into the dealership which fixed the problem over 3-4 visits. They gave me an ES rental for free and their service was immaculate and free so I'm not complaining.

General Comments:

I did an extensive bit of research before I got this car. I list the pros and cons of the car vs. C-class and 3-series in hopes of it helping others with their purchase.

Pros:

Much better equipped than either the C-class or 3-Series (The option prices on competition are too high).

More reliable than other brands (Lexus being the most reliable brand).

Dealership service is amazing (having owned Mercs and Beamers before, Lexus services you much better).

Running costs are very low as the car barely uses any gas.

The AWD package really helps out during winter.

I personally prefer the look over 3 series, I think the C class is better looking, but the IS is gorgeous too.

Lexus maintains its value better than the competition.

Parts are expensive, but still cheaper than both Mercs and Beamers.

Cons:

Power lags behind the competition - I knew that before the purchase, but I wanted something more economical.

Second row seating is very cramped compared to the C-class at least.

Ride quality isn't as smooth as Merc or sporty as BMW.

Overall, I felt considering the options, the price, dealership, and the looks, the IS was a very good choice.