I'll begin by saying that I'm using this for my Guitar Teaching Business.
The events I run are webinars, workshops, and 1:1 lessons, and have been searching for a software solution to handle the bulk of the heavy lifting.

1:1 Private Lessons
I simply create the event for the student and generate the invite. The student logs into his or her own "event". The chat and board allow for easy correspondence and resource uploads. For resources, I used PDFs only. It doesn't support MP3s or videos (but, the video chat can handle all of the video correspondence if needed).

Webinars
I ran my first webinar this past weekend. Again, event setup is a breeze, and importing a guest list via CSV file is a snap. I used SendFox to handle my automated emailing. And, the event worked fine.

Workshops
I set up an eight-week workshop and it will begin this week. I hope that I can update this review to let you know how it went.

Student Feedback
The video was not the best and I noticed that too. The screen sharing images worked fine but the camera image was a little fuzzy and pixelated. I have decent bandwidth and have experienced better visuals with Zoom, Google Meet, Skype, and the other usual suspects. I ran a survey after the workshop and the feeling across the board was "great platform, okay audio and video." My 1:1 students also commented on this.

The sound also took a little bit of a workaround. However, I do realize that I'm not using this app in the way that it is intended.

My Wish List
Better video quality
Better sound quality
I wonder if there's a way to police the people actually attending webinars and workshops as these are paid events. And, not everybody that is invited will pay. (Again, this is probably outside of the company's vision for this app).
And, finally, if there's a way to process payments through PayPal or Stripe. (I apologize, I may be crossing the line here and asking for something that is not part of the company's vision).

Overall
I love this app and can see it only getting better.
I've been looking for a solution to all of my problems and Guestboard ticks most of the boxes.
This is a great platform for hosting events (especially outside of the Facebook ecosystem).
As is, it's been a great addition to my workflow and I will continue to use it.
In short, I'm a fan!

Kudos to Peter and the Guestboard Team!!!