There certainly have been missteps but we'll never know all the reasons. However, the critical lack of components has affected most manufacturers. In the case of the AVM90 we now have a more mature product with features (2.1, Spotify C.) that were lacking early on. I have the AVM60 and plan to upgrade to the AVM90 but I want to see some objective evaluations of the unit compared to other processors. I see the main reason to upgrade as the improved ARC functionality compared to the AVM60, esp since I have 4 subs. I watched a video last night
that detailed the experience of one user who compared the results before and after using the most recent beta upgrade of ARC Genesis (phase and time alignment features). The video is long and tedious but eventually you see that the beta program did not work well (as assessed using REW) but the guy was able to largely fix it with manual tweeks. So maybe it's best to hold off for a while. Until Amir gets an AVM90 in for testing it will be a gamble.