I've owned an 87, 97, and 06 3-series, and recently spent a week in an 08 M3. Those represent 4 different platforms (E30, E36, E46, and E90). What you're looking at is the F platform, which is really a very different type of car than the earlier 3-series BMWs (hence the end of the E platforms). To be honest, I have no interest in them. BMW has been gradually moving away from "driver's" cars towards comfortable/lazy cars, IMO. Just not my bag. I've had a couple of F30 loaners from the dealership and didn't much care for them at all. They didn't feel solid, which is a first for any BMW I've ever seen, and they weren't fun to drive at all. I suspect BMW wants the "drivers" to pop for M models. They're selling the normal 3's to folk who just want a comfortable ride and don't care about having fun.
As for maintenance and cost of ownership, BMW traditionally builds a sold car. I put ~225k on my first two, and had no qualms whatsoever about buying my 3rd with 90k miles already on the clock. In the case of the first car I drove it every single day like Buford T Justice was chasing me. The second I drove for ~50k with a blown head gasket. They're hard to kill. In both cases it was secondary problems that caused me to abandon them. Replacing that head gasket would have cost more than the rest of the car was worth, but the rest of the car was still in good shape. They will need maintenance, and maintenance is pretty expensive. However, I've found that the really expensive stuff just doesn't give out. I suspect on average I've spent ~$2k/yr on repair. Since I pay cash for my cars this works just fine for me.
Having said that, I didn't get the impression those F30s I drove were expected to be low cost, high mileage cars. Wouldn't surprise me to see those things turning pretty expensive after ~100k. My hunch is that most manufacturers are shifting towards a model where everybody leases or buy's former lease cars with 30k on them and turns them around every 3 or 5 years. I don't think they're really making cars with people like me in mine anymore.
So after all of that, I guess what it comes down to is what you want out of a car. Do you want to drive the hell out of it or is it simply transportation. Do you want to own it for the next 10 years, or do you get tired of cars and move on. That sort of thing.