I haven't used Bijan since purchasing Accuseason so I can't speak to the updates from the last 6 or so months however I would say that in my estimation Bijan is in many ways a boutique and perhaps more artistically developed product at least in regards to niche details that improve the feeling of 'life' in the areas listed above. Accuseason is quite a streamlined easy to use product with (at least in the overall world) equivalent enhancements in making the world feel alive and changing on a daily basis with no need for user interaction. From the listed improvements in the works Accuseason (for me) is a better option that I don't have to think about but I miss badly when it isn't present (between reinstallation recently). Performance in SU10 is definitely improved as well over the days of the early beta. Personal choice of course and definitely Bijan started it all and continues to supply perhaps a higher level of fidelity ahead of where Accuseason is at any given time but it does catch up as you can see watching their demonstrations. Both are great products, Accuseason allows one to just not think about it, ever, it just is.
I would very much enjoy being a beta tester however they appear to be full at present (hint, hint). 🙂