To be honest, I think this is a great move for the future of the platform. The team behind Hive have been enthusiastic from the start and have been very successful at getting those tiny little AlertMe / Hive Hub units into a lot of houses. As we all know, those little boxes can do an awful lot more than just listen to a thermostat.
Overall, this is probably the type of deal AlertMe have been aiming at for some time, given the way they changed the business. The only thing we long-termers have to ponder is whether they'll keep the AlertMe servers up and running. I can't see that they cost much to keep ticking over.
So good luck to everyone at Hive! Looking forward to seeing how the platform develops.