the Cloud-Zoo seams to be a good choice for most Rhino 6 customers. I have made a little account creation tutorial for it: https://www.flexicad.com/service/forum/index.php/topic,8766.0.html
Now with the release of Rhino 6, I think 99% of the Rhino 6 customers just want to create an account with their one Rhino 6 license.
Please can you add an account creation option, to add all needed information in one(!) step/form. The current 7 steps to get a running account seam a little bit too much for some users. I get too much support requests about it.