As someone who is likely to be unaffected by the paid update as I only recently joined the S3D family, and I definitely love S3D, please do not take the following too harshly. I think the main points of contention are as follows.
People are irritated they paid $150 for a "premium" software understanding it would be continuously supported and now it is barely ahead of the free softwares that seem to be soon to overtake it, as Prusa continues to pump out meaningful updates. Add Pathio beta recently released by the development powerhouse E3D, yikes. Don’t get me wrong, I love s3d. I’ve been printing for 6 years but just got s3d about 7 months ago, but its not even remotely as far ahead as it once was when I first started printing. There seems to be a track record of inconsistency and it would be extremely challenging to make pricing determinations for updates, I'm guessing which is why none have been mentioned, which doesn't bode well for current and potential customers.
I'm sure many are thinking, what if you pay and s3d puts out no updates for a year? You’re screwed. Only pay for major updates maybe? Well then everyone who didn’t get the last “main” upgrade is certainly screwed/barred on any interim upgrades/updates after the most recent “main upgrade”. S3D seems to lack the business structure to create a long term, active development strategy, while also maintaining a timeline. I don't think I've seen much beyond "we're working on some stuff we'll release eventually." Without a timeline, pricing structure, and expectations, it is definitely much harder to marry yourself to this software.
Please don't get me wrong, S3D is a fantastic software, but you had a 4 year headstart. Recently, S3D seems more reactive than active now that Prusa has really closed the gap, and certainly isn't letting up.
I have big hopes for this update.... whenever it comes out, regardless of price. I just hope S3D can get this car back to a lap ahead. I'm certainly happy to pay for an upgrade if I know that's where we're heading.