Which Android has the Best WiFi connectiviti

[AC Question]

I currently use an iPhone 6 Plus. Before this phone I was a long time Android user, specifically Samsung Galaxy. The reason I change is because I do have poor cellphone signal inside the building I work at and I depend on WiFi signal for calling and texting which was very poor with my Galaxy S5 (call drops every 20 min, and delayed text messages). After seen some coworkers seem to have a better WiFi signal after switching to iPhone I decided to give it a try and sure enough I've never had any problems with calling and texting at work again. With that being said, I got to used to using Galaxy and I will like to go back to an Android. Is there any Android phone that would have better or equal WiFi connectivity quality as an iPhone? Good quality WiFi calling and texting is the most important feature I'm looking for, but I'm tired of this boring phone!