I had nothing to really complain about at Zenkaikon. Although it was one space for Dealers and Artists, the tables are spaced out very well with no obstructions (Dealers were in the center of the room, Artists were along the walls). What interaction I had with staff was great and friendly, traffic was decent for the con size, and table prices were great (as mentioned in the Con details here on this site). If you are local enough, I highly recommend.
Oh, forgot to mention, up until now it was first come first served for getting a table. For 2016 they changed it, with 25/65 of the tables first come first served and the rest are random draw. So if you don't get in within the first few seconds, you still have an equal chance as everyone else who didn't get one of the first 25 tables.