Hi @graybikes! I haven't tested the latest Cero model, but their original was very cool... the company was completely focused on it vs. a range of models, and I was impressed with their decision to use different sized wheels. Here's that older review in case you haven't seen it. I hope to cover their new model sometime soon as well: https://electricbikereview.com/cero/one/
Of course, Tern is also an amazing company that has done a great job. They seem to use Bosch drive systems predominantly vs. Shimano with Cero, but both are leaders in the motor space. I also noticed the enthusiasm and quick customer service from Cero as making them unique. Hopefully others will chime in here with their experience as well.
Good news - the new CERO One is available for preorder now at our website, www.cero.bike. We *may* also be able to connect you with a used first generation CERO One. Send us an email at firstname.lastname@example.org and we'll see what we can do.