There are reports of Wifi issues with the 3 B+. I've had a different experience.
I have NetworkManager installed on my devices. Despite the login warning that wifi won't work, it is able to connect fine with no country configured. It reports a '00' country code - that would need to be changed to get 5 GHz goodness.
Hotspot creation using NetworkManager works as well.
I've not noticed a higher level of connection failures with the B+.
Comitup works with the 3 B+ with no modifications.