I bought a 2003 Z4 ten years ago and thoroughly enjoyed driving it for 55,000 miles. At the age of 52, it was a great purchase. At 62, with bad knees, and 6'3", it became more difficult to get in and out of. And, being a roadster with a small trunk, it wasn't good for more than a quick overnight trip. So, we traded it on a '13 128i convertible and so far, it's a wise decision. Had to special order it since I wanted a manual transmission and was willing to pay only for the options I wanted. Only 1000 miles so far, so it's too soon to determine reliability. The fit and finish is typical BMW qaulity and the engine and transmission are smooth. UPDATE: I've now owned the 128i convertible for three years. It's got 16,600 miles, all trouble free. It's still fun to drive and I got another compliment on its appearance just the other day. It's Vermillion Red with a black top and tan interior. This is not my primary driver, but now that I'm retired, it does get driven more. It's a good combination of being a true sports car, but with more room than a roadster. The 2 series BMW should provide the same benefits since it's basically the same car with a different number.
This 135i convertible with M Sport package is one of the most---no, make that THE MOST FUN--car I have ever owned, and I have owned many, including Jaguars, Corvettes, and Porsches, to name a few. Fantastic engine pulls strong from a dead stop to 7k rpms. DCT transmission is a blast. Handling is sharp. This thing scoots around like a Miata on steroids. The only thing I dislike about this car are the run-flat tires, which I switched out after one week for some non-run-flat Michelins--this immediately improved the ride tremendously. I think this may be the best car BMW makes.
This is my second 135i convertible, and I have over 20k on this car at the time of this review. I was somewhat reluctant to order it with the then-new-to-the-135 7-speed dual-clutch transmission instead of the manual, but I was persuaded by the thought of the lightning-fast shifts and the advantage of being able to select between auto and manual modes. The reality is that in manual mode, and even auto mode for fast acceleration, the transmission is brilliant. But in stop-start, mundane "through the neighborhood" use (where you just want to leave it in auto-mode), the transmission is hesitant, clunky and confused. In other words, where you most want it to be an automatic, it is wanting.
Best car I've ever owned. I have had Corvettes, Jags, Benzes and a multitude of others, but by far my favorite is the 135i convertible. It is a fun, peppy car that strikes an almost perfect balance between ride/handling--and this is with the sport package. Mine has the DCT transmission--it works flawlessly and is so intuitive I rarely use the manual function. Handling is superb. The ride is a bit rough with the OE run-flats. I swapped mine out for non-run-flat Michelins right away--the ride is much improved. IMO, BMW should do away with OE run-flats. They are horrible. Update after driving this car for 25,000 miles. I still love the car, but I wish I would have gotten the manual transmission. The DCT is great if you are driving fast, but for normal mundane around town stuff--which is 90 percent of my driving--the DCT sucks. It has a horrible problem where it is almost as if the car dies when you come to a stop quickly and then try to step on the gas--nothing happens for 2-5 seconds, and then all of a sudden the transmission figures out you want to go and it takes off. This is not turbo lag--the car simply will not move--you can have the gas pedal floored and it feels as if the car shut off--nothing happens for a few seconds, which is scary in some situations. I took it to the dealer and they kept it for a week trying to fix it--they got it improved slightly, but it is still not fixed. I have discovered that, if you slap the gear shift over into sport mode as you are coming to a stop, this takes care of the problem, so, as long as you can plan ahead, you are okay. This won't help in emergency situations, but for most around town driving, I can now at least avoid this problem. Other than the DCT issue, and my previously described disdain for run-flats, I LOVE THIS CAR.
This car is very well balanced and handles perfectly. Nice compact size with plenty of power and acceleration. It will give any car on the road a run for its money. Much less expensive than Porche, Vette, etc but as much or more fun and able to carry 2 additional passengers for short distances. Would recommend the BMW 135i to anyone who is a "driver"