Keywords:Lorenz-like systems Lorenz system Chen system Lu system Lyapunov exponent Chaotic analog of 16th Hilbert problem a b s t r a c t Currently it is being actively discussed the question of the equivalence of various Lorenzlike systems and the possibility of universal consideration of their behavior (Algaba et al., 2013a(Algaba et al., ,b, 2014bChen, 2013;Chen and Yang, 2013; Leonov, 2013a), in view of the possibility of reduction of such systems to the same form with the help of various transformations. In the present paper the differences and similarities in the analysis of the Lorenz, the Chen and the Lu systems are discussed. It is shown that the Chen and the Lu systems stimulate the development of new methods for the analysis of chaotic systems. Open problems are discussed.