I have the 328xd and very happy. The dealer was pushing the diesel last summer and the 328xd price was competitive with 320i
I have not found diesel station availability to be an issue
The gasoline 328 is faster so if economy/range is important you will be happy with diesel.
In summer with a 60/40 highway /city split i get low 40 mpg and about 600 mile range
On a highway trip could get close to 50 mpg if you try
Off the line the diesel torque is very strong.