Among the many challenges introduced by the IPv6 transition process to the Internet community, one of the most difficult was presented to the network operators. All of the existing production networks were forced to reconsider their inner architecture to move towards IPv6. To support network operators in this challenge, the IETF has proposed multiple IPv6 transition and coexistence technologies. Which one of these technologies is most feasible for their scenario, is still an open problem. To support network operators solve this problem, we are proposing a suite of practical evaluation methodologies, exploring various feasibility dimensions of transition technologies. The methodologies are associated with a heterogeneous IPv4 and IPv6 network testbed, which we called the IPv6 Network Evaluation Testbed (IPv6NET). In order to validate these methodologies, we have used them to analyze the feasibility of two open source transition implementations, covering multiple transition technologies. To that end, we are showing how network performance, scalability and operational capability data can be obtained, analyzed and compared.