I had the 435i previously and now the 335i.
Both drive great. Looks wise I prefer the 435i. I like the 4 series look, and have always preferred coupes.
How big is your family? Space in the coupe is actually quite nice. I only had 1 child at the time I had my 435i. Only problem is that it's a 4 seater (hard panel in the middle of the rear seats).
Now I have 2 children and the 335i is more practical to be honest. If it's an option, go with the 435i gran coupe as it has the practicality of the 3 series sedan but 4 series look. If the gran coupe isnt to your liking I'd say go 335i