I emailed the company the other day as they are both made by same one.
They responded that either are good for upvc, windows etc but to remember to rinse well. The sales person's personal recommendation was Viro Sol.
One thing I have found on the data sheets is that Viro Sol isn't good for aquatic life! So if the property has a pond I would be very cautious using Viro Sol. Ubik 2000 doesn't have the same warnings regarding aquatic life.