While the limit equilibrium and finite element methods have been used by the engineers for a variety of slope stability problems for many years, the use of limit analysis has started to attract the attentions of engineers and researchers in recent years. In this paper, the differences between these three major methods will be studied in terms of factors of safety and the locations of critical failure surfaces. From the study, it is found that even with the use of recent versions of finite element or limit analysis programs, surprising and unreasonable results can still be found frequently, and the use of the classical limit equilibrium appears to be robust over various difficult problems with relatively complex geologic conditions. On the other hand, the differences between the three methods can be considered as small for normal problems.