I've switched to using the new Alexa Conversations model. If I have errors in my dialog(s) I get the error messages fairly quickly, but if everything is "clean"... It takes at least an hour, maybe multiple hours for the build to end. I get mixed feedback on the success. The completed build count seems to increment, but the build model check mark never turns green, and I don't think new functionality is available.

I've tried to build a very simple example skill and get same results.

I left this project building overnight, when I checked on it after 24 hours the page still indicated it was building. I could see the 2 dialogs that I had configured. I refreshed the page and everything I had modified yesterday had reverted back to the previous days configuration. I never had this issue with the Interaction model.