Personally, since both sides seem to be ramping up the FUD* factor, I think that most undecided voters will mistrust the information from both sides.
Quite a few undecideds I have spoken to are probably going to vote "Out" for one reason - immigration; by that, I mean controlled immigration, like countries such as Canada, NZ, Oz, etc. At the moment, it would appear the UK must accept anyone from the EU, and most people I know don't think that's acceptable. They find comments by Brexiteers like Gove who says five million Turks are coming to be fairly laughable (much like the
29 million Romanians and Bulgarians Nigel Farage said were coming here), but they see a slow drip, drip, drip gradually wearing down our services.
They're not being racist - they don't want unskilled people from any country, including our old colonies, coming here.
*FUD - Fear, Uncertainty, Doubt