Bogdan wants to know what home assistant should he buy. Leo says it depends on what he wants to use it for. Google Assistant is better for answering questions, and Amazon Echo is better for shopping and consuming music. Both now support making phone calls. Both will work with home automation devices, so he can tell Echo to turn on the lights. In the long run, Google will probably be the best, though.
Can he stream iTunes on either? Leo says no. He would need the HomePod for that. If he wants to do Apple stuff, he'll need an Apple device. One exception is Bluetooth. He can connect it via Bluetooth and then play from the iPhone that way.