[Ifeffit] R-factor and reduced chi square

Hi, I understand R-factor and reduced chi square are statistical ways to see if the model is reasonable (R-factor) and if one model is better than the others (reduced chi square). But how much should I read into it? I have model A and B, I believe A is more theoretical sound than B. but when I fit them using IFEFFIT, the R-factor and reduced chi square of B is slightly better than A (B: 0.03, 28; A: 0.04, 33). What does that tell me? Is my assumption incorrect? Or are they more or less the same? Owen