More reliable than a 335. The 3.0L engine is pretty bulletproof HOWEVER, many other things can go wrong with the car and will be costly to fix.
BMW's are not really known for their reliability in general. The 328i is a "relatively" reliable car I would say.
2007 E90 328i - Titanium Metallic l 19" VMR V710 l H&R Trak+ Spacers l Mtech Rear Lip Spoiler l Eibach Sportline l AA N52 Signature Exhaust l OEM Blacklines l MTEC V3 AE l 6000K HID l Nokya 7000K Fogs l MTEC License Plate LED l Interior LED l 15% Tint l BlackVue DR380G-HD + PMP