I use/used it for it's basic functions, sharpen and denoise and they did a great job until 2.1.2 where things started to get a bit challenging.
I beta for them so I get pre-release and much of my challenge comes from the beta testers conveying that there are challenges. Time is taken to convey the challenges in great detail and the application is released without resolution. The past two version, the application re-opens after it is closed for many windows users myself included and they were aware of the issue. They were told, it was ignored. The removal tool is placing cartoon images randomly in processed images, new functions are released that take hours to process a single image, memory is allocated by TPAI and not released when the application is closed.
They went from a focused, tightly disciplined group to a team that hustles out releases without proper quality control. You are correct, they are constantly adding to the application which should be a significant value but the releases are sloppy or the new functions are slow and difficult to fit into a workflow I don't view that as a positive. And if the minimum requirements for a system continue to change rapidly because new functions are resource hungry or have been poorly developed/written that is not a positive for the current subscribers.
I have been a cheerleader for them for a long time but it's just my opinion they have become rushed and sloppy. New releases should be as close to perfect as possible upon release, not released with know problems. My expectation is that I purchase finished products with minimal bugs, not to continue as a beta tester for a cost.