Several measures intend to imitate the R-squared analysis in this kind of models, but none of them are an R-squared since logistic models are not calculated to minimize variance. For Mc-Fadden measure, values of .2 to .4 are considered highly satisfactory. And if you have alternative models on the same data, McFadden's would be higher for the one with the greater likelihood.
If you are interpreting adjusted Mc-Fadden's, remember it penalizes a model for including too many predictors.