Participants need to send in their personal info, their pick for the best MG and reason to Hobby Japan and Dengeki Hobby. Particulars on participating in this survey can be found in this month's issue for both magazines. 10 lucky draw winners from each magazine will receive a present related to this survey.
The survey will list 10 of the best MGs as picked by the participants and the result will be published on May 25th, separately for each magazine in their July issue. The combined result will be published on Gunpla 30th Anniversary official site on the same day.
My choice for the best MG so far are Acguy and Sinanju Ver. Ka ^^
Images and information are from Bandai Hobbysite's Gunpla 30th Anniversary official site.