I have a 98 528i, 136K miles, it's a mostly nice car, although I've had overheating problems - 3 thermostats, a water pump, thermostat housings in 2004/2005, now it's overheating again maybe - temp needle acting goofy. The car has always been taken good care of. My independent bmw mechanic says I might need a new head gasket : $1500-2000. Ugh. The transmission problem mentioned above is scary....
So I dont know if I'd recommend a 528i....unless you're willing to spend big bucks on repairs.