I would've sworn I posted something about this when Zero announced it on their Facebook page but I can't find it. Anyway, I downloaded the NexGen app from the Android PlayStore and tried it out for the first time yesterday. First thing I had to do was go into Android's bluetooth settings and UNpair my phone from the bike. Then, the app was able to pair with the bike and connected almost immediately. So far it's reconnected twice immediately... something the old app frequently fails to do.
Unlike the old app, I was able to set Neutral Regen to 100%. For some reason with the old app, setting Neutral Regen to 100% was the same thing as setting it to 0%; in order to get maximum regen I had to bring it as close to 100% as possible without actually setting it to 100%
Zero says that right now, you can't use the new app to flash new firmware on your Gen2 bikes; you'll have to keep the old one around for that. However, a question raised on Facebook made me check something for them and the new app returns far less information about the bike than the old app. Not sure why that should be but I can use the new app as an "auxiliary dashboard" and keep the old app around for updating the firmware and checking some of the more esoteric information about the bike.