I absolutely love it. I test drove lot of cars before I got it, some of the more noteworthy were: GTI (liked it a lot, but wanted more performance), a Volvo C30 (same feelings), a WRX (stock it wasn't any better than say a GTI but felt much cheaper, I was disappointed), an Evo X (holy crap that was fun, the wait for boost seemed like forever but the handling was insane, this was my #3), a 370Z (gorgeous sexy car, performance obviously good, but even after a couple test drives I couldn't shake the feeling that I couldn't see out of it and that it was driving me instead of the other way around, but I'd still say it was #2).
Those were all new. Convinced to try a BMW (I kept thinking - I'm not one of *those* assholes), I finally caved in and figured I'd give it a shot. Looked at used for these, because of the price. 3 series was very nice, but I wanted something smaller. Found a 128i, and was immediately at home. Something about the positions of the seat, steering wheel, shifter, pedals, whatever I felt at home. And LOL it had glass all around, I could see out of it. I was immediately ready to have fun with it like I'd been driving it forever. Ended up getting a 1yr old used 135i, went that route over the 128i really just to get the turbo I guess.
Anyhow after 1.5yrs it's been bullet proof so far, no trouble at all. I love it, love it, love it. It's got a very tactile driving feel but it doesn't tire you out. M3 suspension parts and other items (rear subframe bushings are popular upgrades) trasnfer over and only make it better. It's small and funky and to many people it's even ugly. There's hardly any 1-ers around, too, even living in a metro I see one a month maybe. All things that I love.
According to the car itself, I average 22mpg, and that's in stop & go traffic almost exclusively so not too bad. Insurance is about 105 a month, I'm 42 with a clean record for reference.
I won't piss on the GTI, it's an awesome car. But yeah, for me, the 135i was better in pretty much every way. If you want a different car, it's certainly worth looking at one.