go for F30. I am driving a 328i Msport. This is the 7th year clocked 150k. Only replace the wear and tear parts. 1 wheel speed sensor, 1 oil pan gasket. That's all. The most expensive parts is the adaptive suspension, but I consider that as wear an tear. You can always refurbish the shock instead of replacing full set.
The only draw back is the sound insulation for F30 is very bad.