As a chrome app dev (Videostream is our app) the transition has been really annoying. They've given us ample time to prepare for the shutdown and we've developed a new app, from scratch, to work outside of the Chrome app world but they (as engineers tend to do) did nothing to mitigate the disaster of a transition. Through blogs, tweets, etc. directly pointing to the webstore, we have years of SEO built up all pointing directly to what will now be a dead link.
We've been pestering Google for a way to have a redirect or link on that page that says "get the app for windows and mac in its new home over here" but they haven't been very responsive. It's such a shitty way to treat developers who chose your ecosystem and who you did a certain amount of convincing. They have done this to us once before, with their wallet for digital goods, where they shut that down and developers lost any recurring subscriptions they had on the platform.
Basically, google is brutal if you develop on a platform for them that they decide to axe, they really don't think of the people and companies and how they will be affected and we now think twice before choosing to use anything they maintain.