Any M3 really, it is not that I dont like the M3, they are stunning cars in every aspect, But when I bought my S3 I looked at a few cars, and have always looked at 3 series, even the 1 Series m when looking around (not the new one not released yet).
Main reasons, Mostly Size, and 4 wheel drive., Understated, then running costs, then buying cost though that was not really a determining factor. I love the size of the A3, always have loved small hatchbacks. (I am told there is a 3 series 4 wheel drive BMW make for the US, maybe Canada) I got to admit I have never driven an M3, though been in an older ones. a few friends have them and an old M5.
I find a DSG S3 quite relaxing to, so easy to just drive on a grind. and all my quirks I hate with the S3 I think are covered by the RS3
I got to admit as well, although many slate the feel and drive of an S3, again once it is chipped I love it I find the steering really responsive not too light, as for handling again love the 4wd ability to come out of a corner earlier. I love the security of the drive.
When I drove around NBR, with 2 mate both M3 owners, one a CSL both thought DSG was fantastic, and the way you can come out of a corner earlier, the CSL owner has driven a 52 plate M3 around NBR in 8' 33 secs and again he was more than impressed that I could easily hold off a CSL and out accelerate it from a corner, he said for a stock car bar stage 1, it would go around NBR very fast, and these guys are BMW die hards, but all of that is unimportant for me, I am not a racing driver.
It is just a car for me that ticks more boxes for everyday driving.