Trust your designer as far as developing the aesthetic aspects and you seem pleased with the results you've received. So that's taken care of, at least for now.

I suggest trying to put together some focus groups. Front load by briefing one of the groups with information about the company, products, vision etc. I would also keep one focus group as "raw" and uninformed as possible just to get some insights on purely aesthetic aspects of the designs.

Be open to the results and be prepared to kick it all back to the designer and using the feedback.

It's not an easy process but it's an important one. This decision will set the tone of your business and affect market acceptance. Changing your brand identity and design can be tough once you've really built it up in a specific direction. Really studying the results of group can give you very high confidence that you've made the right choice.