welcome to he forum scott
i can't comment on the 320d, but i know a few people here have them...
but the e90s that i have driven, a 320, 325, and 330, all felt very solid and sure footed, and a pleasure to drive! i enjoyed teh loan car i got, which was a 320
bmw services will be, most likely, a shock to the system pricewise after owning a holden... they can be a bit pricey, but not obscene unless something major goes wrong (but then that is a warranty issue right?
the dealer should be ablw to give you an estimate of what the oil and inspection services... i asked when i bought my car