The best integrated amplifier

Hi All
Right now I am using a Marantz PM-KI Pearl amp to drive Esoteric MG-20 speakers. I feel that a better amplifier would give them a bit more get up and go. I would like to stick with an integrated and have short listed:
Pass Labs INT-150
Moon 700i
Audio Research dsi150
GammuT Di 150
As a starting point for auditioning. Now to the question:
Is there anything else I should put on the list?
Any experience with the products listed would be helpful.
Thanks