It really depends on your application if 304L is better than 316L.
I agree that duplexes are a better choice in many applications if CSCC is a concern, which is not always the case. Also, there aplications where the duplex strength does not help. Vessel internals such as screen backing bars in a digester or loose lining in a pulp storage tank, are a good examples of this; they are not stressed, therefore no CSCC possibility and no advantage for strength.
I have heard several complaints, basically, from fabrication shops that wanted to use LDX2101 in lieu of 2205 but it was not available unless they ordered a large quantity. This has been a reported problem on relatively small shop fabricated vessels.
Depending on your application, 304L may be better than 316L (if you stay w/ the austenitic path). Cooking and white liquor plants seem to be this case. There are alot of papers discussing the techanical reasons for this claim. In many applications, it is really a marginal concern.