I have a Frey CC. Very nice bike for the money, but Frey does not yet offer IGH or belt drive. If you want that, Watt Wagons is your answer. Most important you get the aftermarket controller from Watt Wagons. This is very important as the Ultra motor is not very efficient and somewhat unrefined relative to euro-spec mid drive motors. The aftermarket controller upgrades the Ultra to world class territory.
While I love my Frey I will say their support isn't as good as it was. Frey started out as a smaller company but I don't think they have added adequate support staff as they have grown. They really need to hire a dedicated support team. For example, my throttle stopped working. They told me to contact Bafang for warranty. Bafang sent me a new wiring harness and throttle, but I will reed to reroute the internal wiring. I asked Frey for assistance how to wire internally. I also asked them about warranty and whether they would cover labor in a repair such as this. No response, and they ignored my follow up email. I find that unacceptable. I eventually figured it out myself, but I think this would be extremely frustrating for a lot of folks.