Also worth remembering that there’s also the Yamaha PW-X2/X3, Dyname 3.0/4.0, Brose and so on.
From my understanding, and usage of a couple of the designs, the reality is they’re just brushless motors with similar controllers, that simply just draws current to match the load on the system, the basics across them all are the same, again battery design is similar across them as well, we’re talking about 50 year old tech that’s being progressed in many other fields.
The issue for me is how well designed and integrated they are, i have a giant e-reign just now, integration is not great, i wouldn’t buy another if they keep to this standard of design, i had a cube with the bosch gen4, it was good, but died and was refunded, again design of the wiring loom was a bit rubbish.
My main shortlist for any ebike buying now is simple, i check the support network for that bike against my location, i am not going to buy long distance, and i am not going to buy something from a shop that sell ebikes, but have no ability to maintain them, as a minimum i would expect them to be able to field warranty claims and modifications where required by the design organisation. Then after i have confidence in that, i can go look at bikes and pick one i like!