The aim of this paper is to throw some light on the main differences/similarities and dynamics in institutional frameworks, regional/sectoral features and aggregate performances in the eight transition countries that became EU members in May 2004 (8-CEECs). In the second section, a partial review of the main theoretical and empirical literature on the "great transformation" (Kornai, 2006) is presented, with a particular attention to the researches focusing on the relationship between institutional change and economic/employment performance and to the studies considering some regional features of the transition processes. Some stylized facts for the eight CEECs are presented in the third section, by distinguishing (i) initial conditions, (ii) institutional changes and progress in transition and (iii) economic/employment performance (GDP growth, unemployment and employment rates, etc.). In the forth section, the empirical results on some regional (NUTS 3) features (convergence, concentration and specialisation) of the 8-CEECs are discussed. Finally, an attempt to econometrically investigate some determinants of regional income convergence and national GDP and employment dynamics is presented in the fifth section, by highlighting the role of institutional change and some regional features. The main policy implications, concerning both European and national economic policies, are presented in the conclusive section.