S3D did refund my V5 without any hassle. I still use V4 sometimes, I have been using superslicer and prusaslicer 2.6 Alpha 0 with success. I need to play with a test model for a bit to see which gives me the best results. I did print some model plane parts with fair results. I think it's just a matter of dialing in settings. Once I got used to the differences in how Prusa/Super slicer works vs S3D, there are some aspects I like about them better than S3D. The only thing that is only slightly annoying is the lack of an easy way to change the part fan speed by layer. I wish it were an option in the height range modifier. As it is, you can change the part fan speed but inserting the gcode command easy enough with the insert feature. You just have to remember to change it back to the default or original value when done. I would think that could be handled automatically in the height range modifier.
Anyway, I think I have found something I like better than S3D. S3D is not horrible, but I think they have lost track of what is important and are falling behind.