SolusVM is an ideal choice for virtualization and it is a tried and tested option. Though Virtualizor is around for a few years, scalability still appears to be a problem. A small VPS hosting service, but not a medium or bigger player in the field, is claimed to be a good option. Scalability with SolusVM is not a concern.
However, I do believe that most of my clients would prefer the client end of SolusVM more than Virtualizor, but they are both good panels. I hope that SolusVM (v2 or anything) will soon be done and released, that a lot of people will be satisfied with it, but I agree that either one will be perfect. Otherwise, I would just create my own alternative and use it. I use SolusVM and don't intend to step away – partially, but moving back would actually be quite a problem if it was decided.