Finite state machines being intuitively understandable and suitable for modeling in many domains, they are adopted by many software designers. Therefore, testing systems that are modeled with state machines has received genuine attention. Among the studied testing strategies are complete round-trip paths and transition trees that cover roundtrip paths in a piece wise manner. We present an empirical study that aims at comparing the effectiveness of the complete roundtrip paths test suites to the transition trees test suites in one hand, and comparing the effectiveness of the different techniques used to generate transition trees (breadth first traversal, depth first traversal, and random traversal) on the other hand. We also compare the effectiveness of all the testing trees generated using each single traversal criterion. This is done through conducting an empirical evaluation using four case studies from different domains. Effectiveness is evaluated with mutants. Experimental results are presented and analyzed.