Teslas make a lot of sense where the infrastructure is in place. There were a lot of them when I was out in California recently (about 4 miles from the Tesla plant). However, the range is a concern to me. I'd have to rent a car several times a year with a 220 mile range, because there's not the infrastructure in place in most of the country to support a road trip in a Tesla.
As for Ferrari over Tesla, because people buy those cars as status symbols, and it's a Ferrari. I don't think Tesla will be able to compete on thrill of driving that's offered by a Ferrari either, but I guess we'll see when the roadster is actually out (and I'm not just talking about going fast in a straight line). Also, not many people take a road trip in a Ferrari or a Tesla roadster I'm sure, but again, unless you're somewhere with the infrastructure for supercharging, I can't consider the Tesla to have more range, even if it's single charge lasts longer than a single tank of gas.
The other battle that Tesla has is that there is a large percentage of the population that lives somewhere (apartments mainly) that don't have garages for charging.
Finally, if Tesla really is not producing the base modeling until Q1 2019, then the tax credit will be at best $3750, and soon $0, as far as TCO goes.