I recently attended a conference at the Sonic City Complex and it served as a reasonably good option for a small conference venue. It is close to the Omiya JR Station and there were several restaurants and coffee shops in the immediate vicinity. The facilities were quite comfortable in terms of the small exhibition hall and the spacious conference rooms. However, to be quite frank, I was surprised to see this on the list of attractions on TripAdvisor for Saitama and I think, more than anything else, that this is actually quite revealing of the dearth of tourist options for this prefecture. This is indeed a nice modern building built in a relatively pleasing architectural style. However, it is definitely not that noteworthy and NOT in any way worth going out of your way to see.

Nice modern building, but not really that interesting. There is not much to see or do there. You help but see it once you exit the train station.